Minggu, 30 Desember 2007

Word problems in Russia and in America

Recently I had the opportunity (HT Let's Play Math) to read an article "Word Problems in Russia and America" by Andrei Toom. It is an extended version of a talk at the Meeting of the Swedish Mathematical Society in June, 2005.

It made for quite interesting reading.

The article was comparing word problems in Russian and U.S. math books. As you can guess, the former were far more advanced than the latter.

I want to highlight a few things from the article. You're very welcome to download and read it too from the above link.

A problem from a Russian fourth grade book:
An ancient artist drew scenes of hunting on the walls of a cave, including 43 figures of animals and people. There were 17 more figures of animals than people. How many figures of people did the artist draw?

A similar problem is included in the 5th grade Singapore textbook:
Raju and Samy shared $410 between them. Raju received $100 more than Samy. How much money did Samy receive?

Now, these are not anything spectacular. You can solve them for example by taking away the difference of 17 or $100 from the total, and then dividing the remaining amount evenly:

$410 − $100 = $310, and then divide $310 evenly to Raju and Samy, which gives $155 to each. Give Raju the $100. So Samy had $155 and Raju had $255.

A far as the figures, 43 − 17 = 26, and then divide that evenly: 13 and 13. So 13 people and 30 animal figures.

BUT in the U.S., these kind of problems are generally introduced in Algebra 1 - ninth grade, AND they are only solved using algebraic means.

I remember being aghast of a word problem in a modern U.S. algebra textbook:

"Find two consecutive numbers whose product is 42."

Third-grade kids should know multiplication well enough to quickly find that 6 and 7 fit the problem! Why use a "backhoe" (algebra) for a problem you can solve using a "small spade" (simple multiplication)!

I know some will argue and say, "Its purpose is to learn to set up an equation." But for that purpose I would use some some more difficult number and not 42. Doesn't using such simple problems in algebra books just encourage students to forget common sense and simple arithmetic?

(BTW, no matter what number you'd use − "Find two consecutive numbers whose product is 13,806" − I'd just take the square root and find the neighboring integers, and check.)

And this is what Toom also wonders greatly: why do U.S. instructors not teach children to solve many-step word problems using arithmetic only? It is as if the more complex word problems are extinct in the standard textbooks until algebra, and word problems in elementary grades are mostly reduced to one or two-step simple problems.

(I've written about that before, how the word problems found in lesson X are always solved using the operation taught in lesson X.)

Another example, a 3rd grade problem from Russia:

A boy and a girl collected 24 nuts. The boy collected two times as many nuts as the girl. How many did each collect?

You could draw a boy and a girl, and draw two pockets for the boy, and one pocket for the girl. This visual representation easily solves the problem.

Here's an example of a Russian problem for grades 6-8:
An ancient problem. A flying goose met a flock of geese in the air and said: "Hello, hundred geese!" The leader of the flock answered to him: "There is not a hundred of us. If there were as many of us as there are and as many more and half many more and quarter as many more and you, goose, also flied with us, then there would be hundred of us." How many geese were there in the flock?

(I personally would tend to set up an equation for this one but it can be done without algebra too.)

Toom talks about how "real life" word problems are emphasized in America, and "fantastic" problems that could not occur in reality are devalued. For example, a problem such as
"Sally is five years older than her brother Bill. Four years from now, she will
be twice as old as Bill will be then. How old is Sally now?
" may be deemed unfit since nobody would want to know such in real life.

However, like Toom argues, such problems do serve a purpose: that of developing children's logical and abstract thinking and mental discipline. One-step word problems won't do that!

In the U.S. word problems are perceived as "scary"; both students AND teachers tend to be afraid of them, and teachers might even omit solving them. This doesn't help, of course.

Here's a joke that Toom had included in his article, by Lynn Nordstrom:

"Student's Misguide to Problem Solving":

  • Rule 1: If at all possible, avoid reading the problem.Reading the problem only consumes time and causes confusion.
  • Rule 2: Extract the numbers from the problem in the order they appear. Be on the watch for numbers written in words.
  • Rule 3: If rule 2 yields three or more numbers, the best bet is adding them together.
  • Rule 4: If there are only 2 numbers which are approximately the same size, then subtraction should give the best results.
  • Rule 5: If there are only two numbers and one is much smaller than the other, then divide if it goes evenly -- otherwise multiply.
  • Rule 6: If the problem seems like it calls for a formula, pick a formula that has enough letters to use all the numbers given in the problem.
  • Rule 7: If the rules 1-6 don't seem to work, make one last desperate attempt. Take the set of numbers found by rule 2 and perform about two pages of random operations using these numbers. You should circle about five or six answers on each page just in case one of them happens to be the answer. You might get some partial credit for trying hard.


I hope your students do not fit the above joke.

In my books, I've tried to avoid problems that would lead children to the above scenario. I do not claim to be perfect in this; I feel I have lots to learn. But I will keep striving to make problems that do require many steps and that do not "dumb down" our children, but that progressively get more difficult as school years go by.

See also what I've written in the past concerning word problems.

Rabu, 26 Desember 2007

Some good math blogs

I was surprised to find that Denise had included me in her Math Bloggers Hall of Fame. Thanks! I feel honored to be a part...

On her list, I found some new reading material from the other blogs listed. Found some interesting posts right off the bat:

Snowflake math - this is a neat lesson plan. Makes kids thing spatially.

Teaching: The Really Big Number (applied). This is a lesson plan about the problem where you need to find the remainder of 100100.

Both of these are obviously from good teachers. Enjoy.

Selasa, 18 Desember 2007

New Math Mammoth books

As the year is approaching its end, and a new one is around the corner, so are some new Math Mammoth books and other news.

Some new ones are already here, from the Green Series. These are collections of worksheets especially good for teachers who need worksheets on a certain topic or topics but with somewhat varying difficulty. They work good for a review, too:
Also, Math Mammoth Money book has gotten a "sister" version with Canadian coins: Canadian Money.

The news some of you might be interested in is that my Lightblue Series complete curriculum books for grades 1, 2, and 3 will be available as downloads from the beginning of 2008, at Kagi store. The price will be $27 per grade level.

And, the fourth grade material for the Lightblue is coming along, as well. I hope to have it ready in February-March. Also in January I will publish two new books titled Math Mammoth Multiplication 2 and Math Mammoth Division 2. These two will replace the current Multiplication & Division 2 book, and will have better (and very fresh!) material.

Senin, 10 Desember 2007

The 12 contests / the 12 blogs of Christmas

I admit; I think the folks at HomeschoolEstore have come up with a really creative promotion!

They've invited 12 bloggers to host 12 different contests on their blogs, and each winner will get a $50 gift to spend at HomeschoolEstore.

Now, I'm not one of those blogs... In fact I can't even participate in any of the contests since I'm a publisher (my products are sold there). But I do want to let you know... it sounds like loads of fun as well!

You don't have to buy anything to participate. Just go visit the 12 blogs and see the various contests. I visited some and saw a photo contest, one where you need to guess what the children in an old photograph are thinking, one writing contest, one was something about finding a quote and writing about that. And there are more (I didn't visit them all).

They've also paired each blogger with a publisher, and Amy Beth from My Smoky Mtn. Homeschool will be writing something concerning my Math Mammoth books during the contest.

Here's a complete list of the 12 participating blogs:

www.Homeschoolblogger.com/01charger

www.Homeschoolblogger.com/ReviewsbyHeidi

www.homeschoolblogger.com/eclecticeducation

lifeonwindyridge.blogspot.com

www.homesteadblogger.com/TexasRose

triviumacademy.blogspot.com

tnmomwith3kids.wordpress.com

www.homesteadblogger.com/simplefolk

homeschoolblogger.com/mysmokymtnhomeschool

www.homeschoolblogger.com/ClassicalEducation4Me

janne.cc/blog

www.homeschoolblogger.com/Ruth

Oh, almost forgot: you can only enter 2 of the 12 contests.

Kamis, 06 Desember 2007

Algebraic thinking

I downloaded the "balance" worksheet freebie, and daughter liked it. We homeschool and she would be in fifth grade this year if she were in public school. ... My question is about the balance worksheets - where would there be more of that? Stuff that does groundwork for algebraic thinking?

It's not just balance problems that prepare a child for algebra. These are important factors also:
  • a good number sense (e.g. mental math)

  • understanding of the four basic operations, for example how the opposite operations work. Another example: understanding that a division with remainder such as 50 ÷ 6 = 8 R2 is "turned around" with multiplication and addition: 8 × 6 + 2 = 50.

  • a good command of fraction and decimal operations. Understanding the close connection between fractions and division.

  • understanding the concepts of ratio and percent.


You can also simply write her more problems with an unknown. For example:

Write 7 + x = 28 and similar ones, like 12 + x = 99 and harder numbers.

x − 9 = 9 and notice how this is "solved" by adding.

6 − x = 4 and then harder numbers.

The same with multiplication and division.

I would also add one more thing that prepares children for algebra: good word problems -- not such that only require one operation to solve.

Singapore math's word problem booklets are told to be good, and here are some other (free) word problem websites.

In fact, soon I want to talk a little more about good word problems based on a paper I'm currently reading.

Selasa, 04 Desember 2007

The snowy edition of Carnival of Homeschooling

.... is posted at Dewey's Treehouse. Mama Squirrel has done a fine job, go check it out!

Carnival of Homeschooling 101: Snowed in edition

Selasa, 27 November 2007

A tutoring option

I have recently partnered with TutorAndMentor.com to offer an affordable online math tutoring solution for those you might need it.

HomeSchoolMath.net (and blog) visitors will get a 10% discount from their regular rates!

The regular rates are:

Duration Total Savings
1 Month Unlimited $150
3 Months Unlimited $350 $100
6 Months Unlimited $600 $300


... but you get 10% off of those by following the link below, and mentioning "HSM" in the Topic when you schedule your first class.

=> TutorAndMentor.com

* Schedule as many sessions as you want
* Work with us on your weak areas or let us design a personalized curriculum
* Regular progress updates to parents

Quoting Shelly from TutorAndMentor.com:

...from homeschooling perspective, students/parents can either study with us on a per need basis or if they choose then we can follow the curriculum of their choice, teach them regularly, and basically back up their parents either taking care of the entire math curriculum for the whole year or any specific math topic.

We actively engage with parents, seeking their feedback and providing them updates, progress reports from our end.

How online tutoring works?


  • We use ‘Whiteboard’ & ‘VoIP’ technologies of the internet to provide fully-interactive sessions with audio, drawing and typing.

  • No special hardware or software is required by the student.

  • We use ‘global delivery model’ to connect students to tutors across the globe.

  • Our tutors have at least a bachelor’s or a master’s degree in math or engineering and experience of working with children.

  • Students schedule sessions online.

  • Tutor and student login at the scheduled time and start the session.

  • Tutors provide progress reports and feedback to parents.

=> TutorAndMentor.com

Remember to mention "HSM" in the Topic when you schedule your first class to get the discount.

Minggu, 18 November 2007

Pan balance problems to teach algebraic reasoning

Today I have a "goodie" for you all: a free download of some pan balance (or scales) problems where children solve for the unknown:

Just right click on the link and "save" it to your own computer: Balance Problems (a PDF). This lesson is also included in my book Math Mammoth Multiplication 2 and in Math Mammoth Grade 4 Complete Worktext (A part).

The problems look kind of like this:

These can help children avoid the common misconception that equality or the equal sign "=' is an an operation. It is not; it is a relationship.

You see: many students view "=" as "find the answer operator", so that "3 + 4 = ?" means "Find what 3 + 4 is," and "3 + 4 = 7" means that when you add 3 and 4, you get 7. To students with this operator-view of equality, a sentence like "11 = 4 + 7" or "9 + 5 = 2 × 7;" makes no sense.

You might also find these resources useful:

Balance word problems from Math Kangaroo

Algebraic Reasoning Game - a weighing scales game that practices algebraic reasoning

Interactive Pan Balance with Shapes

Balance Beam Activity
A virtual balance that provides balance puzzles where student is to find the weights of various figures, practicing algebraic thinking. Includes three levels.

A Balanced Equation Model from Absorb Mathematics
An interactive animation illustrating solving the equation 4x + 6 = x - 3. Drag the green handles to balance each side. Click the arrow button to reset the animation. On the right side, you'll see links to similar animations of equation solving using a balance.

Selasa, 13 November 2007

From the blogosphere

Just some interesting posts from other blogs:

How to read a fraction from Let's Play math. Denise explains how a fraction is not two numbers, a fraction's "first name" and "family name", the line in it meaning division, and more.

Good Math, Bad Math gives an example of the latter: How the lottery company's game "Cool Cash" had to be canceled in Britain. I had hard time believing this one as well!

And some solid tips of How to get past “stupid” Math mistakes from Wild About Math!

Selasa, 06 November 2007

Carnival of Homeschooling, 97th edition


This week, at Principled Discovery, we are attending classes at Homeschool U, our own virtual university for homeschooling families. Each class is worth three course credits.

Go check it out! Lots to read there!

Minggu, 04 November 2007

Subtraction question

(from a site visitor)
I have a 3rd grader who is struggling with the concept of subtraction. He has tried number lines which he hates to use, says it makes him feel like a baby and also we have tried the concept of "counting up", but he claims he get confused because it is "take away" not adding. What can I do to help him with this concept? He has an easier time with 8 − 2 but when it is 14 − 3 we run into difficulty. I have even resolved to letting him use the calculator. Any suggestions?


I think he needs to understand the concept of subtraction better, first of all.

My book Subtraction 1 deals with the subtraction concept itself and the three ways it is used:

- take away
- difference
- whole/part

He needs to understand those three ways it is needed. It's not "just" for take-away situations.

Secondly, he needs to realize that addition and subtraction are opposite operations, and THAT IS WHY we use addition facts when doing subtraction problems.

After that link is CEMENTED, he will then learn his addition facts such as 5 + 6 = 11 and 7 + 8 = 15 and then learn to use those with subtraction.

My book Add & Subtract 2-A deals with that part.

That's not all there is to it, of course. With a problem such as 14 − 3, we realize first that it won't "change the ten", then we can use our knowledge of 4 − 3 = 1 to solve tat 14 − 3 = 11. So understanding this depends also of his understanding of place value (tens and ones).

Hope that helps.

Jumat, 02 November 2007

Rank #1 in Google search meme

I heard about this from Let's Play Math, and thought it sounded a little fun. It didn't take me too long to find out I come up #1 in Google for these phrases:

singapore's bar diagrams 1.17 M
multiplying in parts 1.8 M
number rainbows 1.7 M
homeschool math blog 1.15M
living loving math 1.5 M

The numbers indicate how many results Google showed (in millions).

The rules are below. If you like the idea, consider yourself tagged!

1. Search for your blog on Google. Try to find 5 different phrases that produce your blog as the #1 hit.

2. You may enclose the search phrase in quotes if necessary, but a search without quotes is preferred.

3. Score your search phrases based on the total number of hits.

Selasa, 30 Oktober 2007

Carnival time


Carnival of Homeschooling is hosted at Sprittibee's. this one is the "yearbook edition"... beautifully done.

Sabtu, 27 Oktober 2007

Speed versus accuracy in math

Just go read this very interesting story at Ragamuffin Studies blog: Taming the speed demon.

Up for some challenge in math? Try contests!

Could a nice math contest spark up some interest and motivation in your student(s)?

I really like the idea of math contests and problems of the week. When my kids get a little older, I'll probably use some problem of the week contest from the Internet.

Typically with problem of the week contests you simply do the problems at home and send the solution over the Internet. You, as the teacher, can be in control of time and additional resources used.

The contest problems are more challenging than standard textbook problems. They "stretch their brain", perhaps even strech mom's brain! But that's all for good. We must not let our students live under the impression that all word problems are solved by the method just studied in the lesson.

I've written about the need for challenging and open-ended problems before. You might want to check those posts out as well.

Some contests publish the names of those who solved it right and some simply publish the right solution. Either way, kids can feel a sense of accomplishment if they get the problem right.

Problem of the week contests are excellent for finding challenging problems and for motivation. There exist several:




Math Kangaroo


And, talking of contests, right now there is a great opportunity to take part in a math contest called Math Kangaroo. It is open for all kinds of students, homeschooled or not. Math Kangaroo is probably the most popular math contest in the world with some 3 million students participating worldwide.

This one is not handled over the Internet, though. The contest is held in dozens of locations across USA and many more around the world. The next competition is held on March 27, 2008, and registration is open at MathKangaroo.org.

All children participating in Math Kangaroo will get a certificate of participation, a Math Kangaroo in USA T-shirt and some other souvenirs. The top winners get a certificate of excellence and prizes.

So this sounds like an excellent opportunity for students to experience mathematics in a little different way. The website has past problems that you can use for practicing up for the contest — or just use them for additional challenging word problems.

Selasa, 23 Oktober 2007

Multiplying in parts and the standard algorithm

I haven't blogged for a while but I've been thinking about this topic for a little while now. It is your multiplication algorithm, also called long multiplication, or multiplying in columns. I also happen to be writing a lesson about it for my upcoming LightBlue series 4th grade book.

The standard multiplication algorithm is not awfully difficult to learn. Yet, some books advocate using so-called lattice multiplication instead. I assume it is because the standard method is perceived as being more difficult. But let's look at it in detail.

Before teaching the standard algorithm, consider explaining to the students multiplying in parts, a.k.a. partial products algorithm in detail:

To multiply 7 × 84, break 84 into 80 and 4 (its tens and ones). Then multiply those parts separately, and lastly add.

So we calculate the partial products first: 7 × 80 = 560 and 7 × 4 = 28. Then we add them: 560 + 28 = 588.

If you practice that for one whole lesson before embarking on the actual algorithm, how much better prepared the kids will be!

Next, they will see the standard way of multiplying:


2 
84
× 7

588


Obviously, the steps here are the same. You multiply the ones first: 7 × 4 = 28, write down 8 of the ones, and carry the 2 of the tens. then you multiply 7 × 8 = 56, add 2 to get 58 and write that down in tens place.

What about this way of writing it down?


84
× 7

28
+ 560

588


It uses a little more space, but the underlying principle of multiplying in parts is more obvious.

It works with two two-digit numbers as well:



 84
×   47

28
560
160
3200

3948


Now, the individual multiplications are 7 × 4, then 7 × 80, then 40 × 4 and lastly 40 × 80.

Lastly, I'll touch on lattice multiplication. It uses the same exact principles; however I am not sure if it makes the underlying principle any more obvious to the students than the standard algorithm (and it does take more time and space).

8 4
+---+---+
|5 /|2 /|
| / | / | 7
5 |/ 6|/ 8|
+---+---+
8 8

Answer 588.

Check out Lattice Multiplication to learn how it's actually done; it's hard to explain without images.

Either way, you NEED to explain multiplying in parts to the students. In this case it's not enough just to be able to go through the motions of an algorithm, because multiplying in parts is so needful in everyday life, and later in algebra (distributive property).

Consider for example these mental multiplications you might encounter while shopping:

5 × $14.
Just do 5 × $10 = $50 and 5 × $4 = $20, and add those. Answer $70. I'm sure most of us are quite used to doing such simple products mentally.

4 × $3.12. Go 4 × $3 = $12 and 4 × 12 ¢; = 48 ¢, and add. Answer $12.48.

Jumat, 19 Oktober 2007

Denise's fraction quiz

I want to point out to you a post by Denise at Let's Play Math. She has a quiz concerning fraction rules: can you explain to your children why this way or why that way, as concerning fractions?

Quiz: Those frustrating fractions

QUOTE:
Question #1

If you need a common denominator to add or subtract fractions, why don’t you need a common denominator when you multiply?

Maybe you can explain why, maybe you can't. But don't worry. She's going to continue the topic and explain all of these, on her blog. Don't miss that.

Rabu, 17 Oktober 2007

From the mouth of a child

Background: my daughter has been learning about 3-digit numbers and she's pretty confident with numbers that have hundreds now. She's also heard us adults mention some bigger numbers.

Today she said that she knows how the numbers go:
"Hundred, thousand, million, googol, and gamazon."

What's a "gamazon"??

It's a new number she made up, which "comes after googol and nine hundred ninety-nine."

I guess she's learned something anyway.

Selasa, 09 Oktober 2007

Archimedes knew more than we thought

This story is fascinating; they found a long-lost works of Archimedes under the text of a prayer book, and used modern technology to "see" under the prayer text.

After the text was recovered, it was discovered that Archimedes actually found some of the principles of calculus, and used them to figure out volumes and areas. He dealt with "actual" and "potential" infinity, which is exactly what calculus is about.

And he lived thousands of years before Newton!

A long-lost text by the ancient Greek mathematician shows that he had begun to discover the principles of calculus.

Jumat, 05 Oktober 2007

Word problems in Singapore math and bar diagrams

If you're interested in Singapore math's word problems, and how their bar diagrams work, check out this blog entry by Denise at Let's Play Math:

Pre-algebra problem solving: 3rd grade

She goes through a bunch of word problems from Singapore Math 3-A book, and explains both a solution based on algebraic thinking, and a solution with bar diagrams.

It's good reading for all of us who teach, actually.

Rabu, 03 Oktober 2007

Math card game for all four operations (elementary)

I'm sure youngsters will like this card "game"! I'm going to try it with mine.

Actually it's not really a game, but a fun way for kids to write some of their own math problems using a deck of cards. She even provides a free printout:

Little Blue School: Math Card Game for Addition, Subtraction, Multiplication, Division

HT: This week's Carnival of Homeschooling

Selasa, 02 Oktober 2007

Factoring worksheets

I took time yesterday to make a new worksheet generator. I always enjoy building those; I like simple programming like that and the math in it.

But while doing it, I almost felt I should have been answering emails or doing some of the other projects I have...

Anyway, here it is:

Generate free factoring worksheets - factorize numbers to their primer factors.

Senin, 01 Oktober 2007

Math Mammoth and other curricula

I wrote some thoughts concerning the comparison between Math Mammoth Lightblue series and other homeschool math curricula.

It's not complete, and I'd appreciate your thoughts, as well, to add to the page.

Selasa, 25 September 2007

Math readers

I've had some fun building this page about math readers, or "living math" books for my main site. The list is not terribly long yet, but it will grow, I'm sure.

I discovered that Amazon has all kinds of new "widgets" available to promote their products. What do you think of this? It is a slideshow featuring MathStart readers by Stuart J. Murphy. Hover your mouse over it:



Math story books offer children an interesting way to learn math concepts, to get interested in mathematics, and to explore some fascinating topics outside of the main curriculum. It is one way to bring math to "life". Kids are almost sure to enjoy it.

On my page, I list for example Cryptoclub, a fascinating storybook that teaches how to encrypt and decrypt secrete messages, or The Adventures of Penrose - THE MATHEMATICAL CAT, in which you will encounter many fascinating mathematical topics from fractals to tessellations, or many books for little kids.

I was thinking putting all of that on a blogpost, too, but it's just "duplicate content". Maybe I'll feature a few of them here soon.

I realize not everyone can buy many math readers on top of their regular school books, but try find some of these books in your local library!

Minggu, 23 September 2007

Carnival of math

You might not have heard about it, but there exists a blog carnival for math, too. I submitted my rainbow entry into the latest one.

Not all of the entries there are higher math, by the way, such as MathMom's Calculator rant or Puzzler puzzled from JD2718.

If interested, go check it out: Carnival of math, edition 17!

Rabu, 19 September 2007

Humorous short history of mathematics

Enjoy:

A Very Short History of Mathematics

This is how it starts:

MATHEMATICS is very much older than History, which begins* in +1066, as is well known; for the first mathematician of any note was a Greek named Zeno, who was born in -494, just 1,559 years earlier. Zeno is memorable for proving three theorems: (i) that motion is impossible; (ii) that Achilles can never catch the tortoise (he failed to notice that this follows from his first theorem); and (iii) that half the time may be equal to double the time. This was not considered a very good start by the other Greeks, so they turned their attention to Geometry.

continue here...

Hat Tip to Let's Play Math.

Senin, 17 September 2007

Tips for teaching integers

The main struggle with integers comes, not with the numbers themselves, but with some of the operations. There seem to be so many little rules to remember (though less than with fractions).

Some good real-life MODELS for integers are:

- temperature in a thermometer

- altitude vs. sea depth

- earning money vs. being in debt.

When first teaching integer operations, tie them in with one of these models.

I'll take for example the temperature.

Assuming n is a positive integer, the simple rules governing this situation are:

* x + n   means the temperature is x° and RISES by n degrees.
* x − n   means the temperature is x° and DROPS by n degrees.

It's all about MOVEMENT — moving either "up" or "down" the thermometer n degrees.

For example:

  • 6 − 7 means: temperature is first 6° and drops 7 degrees.

  • (-6) − 7 means: temperature is first -6° and drops 7 degrees (it's even colder!).

  • (-2) + 5 means: temperature is first -2° and rises 5 degrees.

  • 4 + 5 means: temperature is first 4° and rises 5 degrees.

These simple situations handle adding or subtracting a positive integer. Practice those first, until kids are familiar with these cases.

The remaining cases to handle ar adding or subtracting a negative integer:

  • (-2) + (-5) would mean: temperature is first -2° and you "add" more negatives so it gets even colder.

The last case is least intuitive one:

  • 1 − (-5) or subtracting a negative integer. I personally just remember the little rule of "two negatives turns into a positive".

    Some people explain it this way. In (-7) − (-3) you can think that you have 7 negatives at first, and you "take away" three of those negatives, leaving -4.

    This rule of "two negatives makes a positive" might seem counterintuitive at first, but it is needful so that many principles of mathematics can continue to apply (for example distribuitive property).


See also an excellent treatise of integers vs. submarine depth at Text Savvy. Excerpt:

"When you add or subtract with integers, you are NOT combining collections or extracting from collections; you are moving in certain directions."


The "collections" idea does work nicely, for ADDITION:

  • 7 + (-4) means you have a collection of 7 red balls and 4 blue balls. A pair of one red and one blue ball "cancels" or becomes zero. Total therefore will be 3 red balls.

  • (-3) + (-9) means you have 3 blue balls and 9 blue balls more. Total 12 blue balls, or -12.


However, this "moving" idea is exactly how I have always intuitively done simple integer problems — except adding (negative) + (negative) and subtracting a negative, which I change to adding a positive.

Some books might present the rules for adding integers this way:

  • If you add two integers that have the same sign, add the absolute values and put the same sign as what the numbers had.

  • If you add two integers that have a different sign, subtract their absolute values and the answer will have the same sign as the number wiht greater absolute value.

Then they instruct to change the subtraction to addition; for example 5 − 7 becomes 5 + (-7) and (-4) − 2 becomes (-4) + (-2), and 5 − (-3) becomes 5 + 3.

While these are technically totally correct, I find it SO much easier to use the "moving" idea for most quick integer calculations. It is easier to start that way, and then learn these other rules to be used with more complex expressions, such as when adding many integers, or with negative and positive decimals.

Please feel free to download a simple integer addition and subtraction worksheet that practices some of these ideas (from Math Mammoth Grade 6-B Worksheets collection).

You will also benefit greatly from reading my previous article on teaching integers, which goes through all four integer operations.

Jumat, 14 September 2007

Number rainbows to learn subtraction facts

I thought some of you (those who teach second grade) might enjoy my NUMBER RAINBOWS. The idea is that you connect two numbers with an arc if they add up to the particular number, such as 13.

number rainbow for 13

Then, the child can use it as a reference when subtracting from 13 or when doing subtraction drill. You could first drill subtraction facts WITH the rainbow (such as 13 − 4, 13 − 7 etc.) and then without.



You would also ask the child to reproduce the rainbow - and color it, of course! These make for quite pretty math facts practice, don't you think!

I'm going to add these to my Add & Subtract 2-A book.

Kamis, 13 September 2007

Math Manipulatives at my Amazon Store

I don't get around doing much editing of my Amazon Store, but today I was prompted because someone asked me to write a guide for manipulative use. So I'm doing a writeup on them, but also went to Amazon to see what they had.

So I added various ones that I thought might be useful to my Amazon store:

I was disappointed that there aren't any really cheap abaci there. The one abacus with 5 and 5 alternate color beads was quite pricey. Most of them had 10 beads the same color.

Other ones I included were:
- base ten blocks
- cuisenaire rods
- fraction circles or tiles
- scales, thermometers, measuring cups

Math Manipulatives at Amazon store

Rabu, 12 September 2007

Prof. Lynn Arthur Steen and reform mathematics

Dave Marain at MathNotations has conducted an online interview with Prof.
Steen, one of the principal architects of the original NCTM Standards
and one of the most highly respected voices in reform mathematics
today.

This is how Dave describes the interview:
His replies to my questions are thoughtful, honest and
provocative.

Regardless of whether one agrees or disagrees with Prof.
Steen's views, we need to open up this kind of dialog in order to end
the Math Wars and move on in the best interests of our children.


In this first part of the interview, prof. Steen talks about for example the incoherency of math standards in various states learning basic arithmetic facts.

Selasa, 11 September 2007

9-11 song

Please enjoy "America Cried" (a 9-11 memorial song) by Rockabilly.US

Minggu, 09 September 2007

Math Mammoth placement advice

For those of you who are considering buying my Blue Series books, I've created a document that should help in the "placement".

For each of the books about addition, subtraction, multiplication or division I ask you several questions concerning what the child can do or understand.

Answering those you should be able to decide where the particular book is needful or not.

See more: Math Mammoth placement advice.

It does not as of yet contain any tests, but maybe in the future.

Kamis, 06 September 2007

Does the child need to add completing the ten?

Question:
...have an other question about using your worksheets for my daughter. She is six years old - home schooled.
Currently, we are using Addition & Subtraction 2

She is able to add and subtract any numbers from 1 to 100 but when I try to explain "complete the ten" concept, she doesn't like thinking about it. She would rather solve 9+6 by counting on the finger 6 after 9 ... . She complains that I have to first subtract then add to make 10.

My question is: Should I let her complete the exercises without making her think in this manner?


It is important that she understands the IDEA in completing the ten. I gather that she does indeed understand the idea, but doesn't want to do it, since you'd have to both subtract and add, right? She just likes to do one operation, not two?

The adding though, is really easy, because you add 10 + 5 or 10 + 7 or something to ten. If she's counting with fingers, she's not yet seeing the easiness of this adding. It is also faster to do 9 + 6 by first subtracting one from 6 (getting 5), and then adding 10 + 5, because you can do 10 + 5 really easy: it is one ten and five, or we call that fifteen.

Of course she must understand place value to realize how easy that addition is.

Now, the goal is ALSO to eventually memorize the answers. You might let her know that she can't always count with fingers to find 9 + 6 but a quicker method is needed.

You can let her do some exercises "her way" for now as long as she also is able to understand and do the "complete the ten".

But come back to this idea how completing the ten makes the whole calculation easier and quicker. She WILL need to understand the idea when studying CARRYING in addition, (I mean to totally understand how it works. I realize kids can learn carrying mechanically as well.)

So you can say 1-3 months later reprint some pages and try again.

Selasa, 04 September 2007

Review of Flatland: The Movie

flatland the movieI recently had the opportunity to watch Flatland: The Movie. It is a short, educational 35-minute animated film based on an old novel called Flatland.

I thought the movie was quite interesting and entertaining, and my husband felt the same way. We both liked watching it. The animations are excellent, the "voice acting" of the cast is very good, and the whole thing is very well made — thus very enjoyable to watch.

The storyline includes a world set in two-dimensional plane called Flatland. Its inhabitants are simple geometric shapes such as triangles, squares, pentagons, hexagons, and so on. Circles are the evil bosses of Flatland.

Arthur the square hears spherius
Arthur hears Spherius in his living room.


The main setting includes Arthur the Square who is parenting his oh-so-curious granddaughter Hex. Arthur goes to work in a "squaricle" in some office, and has (of course) a circle as a boss.

Hex starts contemplating about the third dimension, but since that is "heresy" and unimaginable in Flatland, Hex's investigations eventually get her and Arthur into trouble. But there is a "savior" — a sphere called Spherius from Spaceland who wants to educate the citizens of Flatland about the existence of the 3-dimensional world.

The interactions between these shapes express plenty of irony that makes the film fun to watch for older teens and adults — and can maybe make them think a little deeper about the prevailing "doctrines" that they are fed everywhere. Just like the shapes in the Flatland had never considered the possibility of a third dimension and rejected it as "heresy", even so we ourselves might be in a similar position (concerning something else), without realizing it.

I wouldn't recommend this movie for early elementary school or younger children because of the strong emotions expressed by the evil circles. Also, young children might not catch on to some of the main themes of the movie, the irony, nor the mathematical ideas. I couldn't put an exact age limit to this though; is up to the parents to decide, of course.

From a mathematical point of view, the movie just deals with a few concepts (after all, it is only a half-hour long). The whole theme revolves around the inability of 2-dimensional figures to grasp 3 dimensions. This is presented really well in different parts o the story. In his dream, Arthur explores all the dimensions up to 3:

Also, I really liked the extra interview on the DVD which has a math professor discussing the intriguing possibility of a fourth dimension, and some neat illustrations.

Apart from the mathematical content, one could analyze this movie's themes (accepting new truth vs. sticking to the current ideology) for an English class project as well.

The website FlatlandTheMovie.com has photos, info on cast & crew, news, the trailer, and a store.

You can also see the official trailer below:



(Note: If you've read the book, you might wonder if the movie goes into gender issues and how women's position in the society is presented. This movie totally omits that part of the book. For example, Arthur's wife is a square just like Arthur is.)

Senin, 03 September 2007

Download issue

Update: The problem below has been fixed. It had to do with my server's configuration.


For my recent customers:

There is some kind of unexpected glitch in Kagi's download script. I'm working on the issue, hopefully it all gets fixed soon.

That script has been working just perfect for all these years. But not since August 30 and I'm not yet sure what happened or what is causing the problem.

Meanwhile, the download links will give a 404 error, BUT not to worry. I will email the files to you directly so you will get the book(s). If you have questions, just email me.

Maria Miller

Selasa, 28 Agustus 2007

Percent of change

When some quantity changes, such as a price or the amount of students, we can measure either the absolute change ("The price increased by $5" or "There were 93 less students this year"), or the percent change.

In percent change, we express WHAT PART of the original quantity the change was.

For example, if a gadget costs $44 and the price is increased by $5, we measure the percent change by first considering WHAT PART $5 is of $44. Of course the answer is easy: it is 5/44 or five forty-fourths parts.

To make it percent change, however, we need to express that part using hundredths and not 44th parts. this happens to be easy, too. As seen in my previous post, you COULD make a proportion to find out how many hundredths 5/44 is:

5/44 = x/100

To solve this, you simply go 5/44 x 100, which is easy enough to remember in itself. In fact, this is the rule often given: you compare the PART to the WHOLE using division (5/44), and multiply that by 100.




There were 568 students one year, and 480 the next year. By how may percent did the student population decrease?

You first calculate the absolute change, which is 568 − 480 = 88. Then we find what part of the original population is 88 (it is 88/568), and express that using hundredth parts (percents):

88/568 x 100 = 15.49%

The student population decreased by 15.49%.




Often we are given the opposite problem: we know the percent of change and the original situation, and are asked about the new situation.

The price was $4.55 and increased by 14.78%. What is the new price?

Here, we'd need to find the price increase, or the absolute change in price first. We know the percent part of the total (it is 14.78/100) and the total amount, so multiplying those we get the part as a dollar-amount: 14.78/100 x $4.55 = $0.67249. So this is the increase. To find the new price, add the increase to the original: $4.55 + $0.67249 = $5.22249 = $5.22.

Instead of multiplying by 14.78/100, it is far quicker to multiply by 0.1478 — or to change the percent-amount 14.78% to a decimal 0.1478 and multiply by it.

And, since in the end we need to add the original total, the whole calculation looks like this:

0.1478 × $4.55 + $4.55

Here, using distributive property we can make it look like this:

= $4.55 (0.1478 + 1) = $4.55(1.1478) = 1.1478 × $4.55

So it can all be done in one multiplication. Instead of multiplying by the decimal 0.1478, you add 1 to it before multiplying.




Then one more possible problem type is that you know the percent of change and the actual change amount (absolute change), and are asked the original and/or the new total.

The price increased by 13%, or by $10.14. What was the original price?

Let the original price be p. Then you can build an equation based on the idea that the price increase is 13% of p:

0.13p = $10.14   or   13/100p = $10.14

p = $10.14/0.13 = $78.

The new price would be found by adding.




Some other lessons to read are below:

Percent Of Change - Lesson and Problems

General Increase and Decrease Examples from Purplemath.com

Percent of change calculator - enter the original and the changed quantities, and it calculates the percent of change.

PERCENT INCREASE OR DECREASE lesson from TheMathPage.com

Sabtu, 25 Agustus 2007

A free download of a digital Algebra 1 book

Kinetic Books Algebra 1 looks really interesting! It is not really just a book, but software, or a digital interactive textbook.

It contains text, interactive problems and activities, and a scoring system all on the computer. Students can get step-by-step assistance in the form of audio hints and one-click access to relevant examples.

See a demo here. But the best is that the company Kinetic Books is even offering a free download of the product till September 30!

That really sounds fantastic, so if you have algebra 1 student(s), don't fail to take advantage of this tremendous offer.

Jumat, 24 Agustus 2007

Equation wizard


Back last spring I promised I'd write something about this tool, so here goes.

Equation Wizard is a software, a tool, that solves first, second, third, and fourth degree equations, simplifies expressions, and calculates values of complex expressions.

I had my assistant use it when checking and making answers to my Algebra 1 worksheets.

Based on our experience, the tool works really well and was useful, for example with rational expressions, or checking answers to equations.

The two features I was missing were:
1) The ability to solve (even simple) systems of equations. There's quite a bit of work when solving a bunch of these by hand!
2) The ability to give exact roots (in our case to second-degree equations). It only gave them as decimals.

See screenshots and more here:
Equation Wizard
You can even get this software for free, with something called "TrialPay".

TrialPay allows you to purchase products by trying something else. Sign up with any one of our preselected partners and we will pay for your product.

Kamis, 23 Agustus 2007

Measure the circumference of the earth - contest

I got word of an interesting contest where school children will form teams and attempt to measure the circumference of the Earth using the same method as Eratosthenes used back in ancient times.

Any students from USA, Mexico, and Peru can form these teams, whether homeschooled, after-schooled, public schooled or whatever.

Whether you will participate or not, go see the animation that explains the method Eratosthenes used (in the left sidebar).

This sounds like an exciting opportunity to connect geometry, measuring, and math history in a project!

And here's some more information:



Please help us get the word out on this new, exciting student centered event!

Measure Your World!

Join us this fall as we pilot a new student-centered project where teams from the United States, Chile, and Mexico partner to replicate the technique introduced by Eratosthenes to determine the circumference of the Earth. Around 240 BC, Eratosthenes used trigonometry and knowledge of the angle of elevation of the Sun at noon in Alexandria and in Syene to calculate the size of the Earth. Windows to the Universe, Educared, and CREA are working together to offer school children in the U.S., Chile, and Mexico the opportunity to form partnerships, take local measurements, and collaborate using the Eratosthenes method to Measure Your World.

All of the information necessary to participate in this pilot student project can be found on the Measure Your World Web sites (www.measureyourworld.org and www.MideTuMundo.org). Student teams must have a parent or adult sponsor to participate. At least one of the team members or adult sponsors must be fluent in both English and Spanish. This event is open to all students in the three participating countries and does not have to be affiliated with a formal K-12 school. Home-schooled children and children participating in after-school programs (e.g. the Scouts, 4-H, etc.) are welcome to participate.

In addition to taking the measurements and calculating the circumference of the Earth, student teams will be encouraged to learn more about their partners in the other participating countries. Suggested activities to promote cultural exchange can be found on the Web site.

Registration for the Measure Your World event will be open from August 13 — September 14, 2007. Student teams will be notified of their partners by September 21, 2007. The time period for taking the measurements will be September 29 till October 7, 2007.

Changes in the blog appearance

I upgraded the blog template to the new one that Blogger provides, and then added the searchable "labels" in the side bar.

So now you can click on any of those "labels" (down on the right side), and find my past posts on that topic. I've written nearly 300 posts since I started the blog (in late 2005). Of course not all of those posts are of mathematical topics, but there is still quite a bit of material that is still as good as ever.

Hope this new feature improves the functionality of this blog. Enjoy reading!

Selasa, 21 Agustus 2007

Some percent basics

The word "percent" means "per hundred", as if dividing by hundred — a hundredth part of something.



We treat some quantity (say 65 or $489 or 1.392 or anything) as "one whole". This "one whole" is then divided to hundred equal parts in our minds, and each such part is one percent of the whole.

If the "one whole" is 650 people, then 1% of it would be 6.5 people (if you have a practical application, you'd need to round such an answer to whole peoples of course).

If the "one whole" is $42, then 1% of it is $0.42. Also, 2% of it would be $0.84.

So to find 1% of something, divide by 100.
To find 24% or 8% or any other percentage, you can technically first find the 1%, then take that times 24 or 8 or whatever is your percentage.





For example:
To find 7% of $41.50, first go $41.50/100 to find 1% or 1/100 of $41.50, then multiply that by 7. But this is the same as (7/100) x $41.50, and 7/100 is 0.07 as a decimal. In most calculations, it is more practical to use decimals instead of this "divide by 100, then multiply" stuff.

So to find 7% of $41.50, I simply calculate 0.07 x $41.50 with a calculator.

To find 10% of something, you could first divide by 100 and then multiply by 10, but it's far quicker to simply divide by 10.

For example:
10% of 90 is 90/10 = 9.
10% of 250.6 is 25.06.

When you can find 10%, it's so easy to find 20%, 30%, 40%, etc., and 5% of anything just by using the 10% as a starting point.

For example:
20% of 52. First find 10% of 52 as 5.2, then double that: it is 10.4.

Example:
A gadget costs $48 and is discounted by 15%. What is the new price?

Imagine the price $48 is divided to 100 equal parts. Then you take a way 15 of those parts. That leaves 85 of those parts - what is the dollar amount that is left? Remember you're not taking away $15 but 15% of the total.

The student needs to realize that $48 is 100% - a "one whole", and 15 of those 100 parts will be taken away.

Solution:
10% of $48 would be $4.80.
5% of $48 would be $2.40 (half of 10%).
So 15% of $48 is $7.20. Subtract that from the orignal price to get the discount price of $40.80.
With a calculator, I'd go 0.85 x $48. (MAKE SURE YOU FIGURE OUT WHERE THE 0.85 COMES FROM!)

How many percent is it?


Of the class of 34 students, 12 are girls. How many percent of the class are girls?

Here, the "one whole" is 34, the whole class. The problem is, if that 34 "one whole" was divided to 100 parts, how many of those parts would we need to make 12 students?

Or, you could compare 34 people side-by-side with 100 "something". Imagine all those 34 people put head-to-toe so they form a long line, and those 12 girls are at the one end of that line. If you'd find 100 equal-size measuring units that would total exactly the same length as your people-line, how many of those measuring units would the 12 girls equal?

This easily leads to a percent proportion:

12/34 = x / 100

Solving x, you'd get
x = (12/34) × 100.

After you do this kind of proportion a few times, you notice that each time we just compare the part to the total using division, such as 12/34 in my example. So it's quite fast then to just write that directly, when solving "what percent" problems.

For example:
A $199 guitar was discounted by $40. How many percent discount was that?

Here, the "one whole" is the original (total) price, $199. It's simply asking how many percent is 40 of 199? Just calculate 40/199, and multiply the given decimal by 100 (which is easy to do mentally).

Hope this helps some. We'll tackle the percent of change next time.

Minggu, 19 Agustus 2007

Master's degree in mathematics teaching and learning

First of all, I've updated my post about the percent problem — just scroll down to it.

Then, I thought maybe I have some math teachers in my readership that might be interested in a new Master's degree program offered by the university of Drexel, in collaboration with the Math Forum!

Knowing how much expertise the folks at Math Forum have this might be a unique opportunity for those math teachers who want to extend their education.

Online Master's in Mathematics Learning and Teaching - "Preparing teachers to incorporate creative, problem-based, student-centered instruction in their classroom."

The rest of you... can just continue reading my blog : )
I will post some more about the concept of percent soon.

Kamis, 16 Agustus 2007

Latex to images - online tool

Here's a handy math tool for those who know Latex (university folks and such). You type in a n mathematica expression using Latex language, and it makes an image. It even gives you a readily copyable code you can paste to a webpage.

Texify.com.

Here's an example of one such image; it's hotlinked from their server.

x=\frac{-b\pm\sqrt{b^2-4ac}}{2a}

Rabu, 15 Agustus 2007

So many percent more

Updated with an answer... see below

I'm continuing to catch up after vacation, and spotted a good discussion about problems with percent, at MathNotations. (via Let's Play Math blog).

Here's a problem to solve, first of all:

There are 20% more girls than boys in the senior class.
What percent of the seniors are girls?


The answer is NOT that 40% are boys and 60% are girls...

You see, let's say there were 40 boys and 60 girls, 100 students total. If there are 40 boys, then 20% more than that would be 40 + 4 + 4 = 48 girls and not 60!

Try solve it. I'll let you think a little before answering it myself. Don't just rush over to the Mathnotations blog either! Use your thinking caps! I've already given you a big hint!

Update:
You can easily solve this problem by taking any example number for the number of boys. Like I did above, if you have 40 boys, you'd need 48 girls and there'd be 88 students total. What percent of the seniors are girls then? It'd be 48/88 = 0.545454... ≈ 54.55%. And 45.45% are boys.

But the same works even if you choose that there'd be 10 boys, which then means that there are 12 girls, and then the percent of girls in the class is 12/22 * 100% = 54.55%.

NOTE that this problem includes two DIFFERENT "wholes". First of all, it says "There are 20% more girls than boys in the senior class." This is a comparison, and the total number of boys is the "one whole" or the "100%". The number of girls is 20% more, or 120% of the boys.

In algebra terms, if there are p boys, then there will be 1.2p girls.

Then the final question involves a totally different "one whole" or 100%: it asks how many percent of the seniors are girls.

So the group of seniors becomes the 100% or the "whole", and all percent calculations are based on that. Therefore one will then compare the number of girls to the total number of seniors.

In algebra terms, the final answer as a decimal is 1.2p/(p + 1.2p) = 1.2/2.2

See also Denise's post about searching for the 100% in percent problems.

Selasa, 14 Agustus 2007

Geometry fun with GeoMag


While on vacation, a friend of mine gave my older daughter a set of Geomag. You might already know about it, but it was new for us.

This has proved to be a fantastic learning toy! She's thoroughly enjoying building various shapes.

For example, she made a cube with sides 2 bars long and was proudly explaining to me how to do it: "First do a square, then put legs up from each corner, and then another square."

I made a tetrahedron that also had 2 bars on each side, according to the model. She thought it was neat and built that one several times herself last night.

I can see how the toy can help build geometric insight and beautifully demonstrate the common three-dimensional figures.

We've already ordered another set to accompany the small 42-piece set she got. You can find Geomag kits of various sizes and colors at Amazon.

Senin, 13 Agustus 2007

A girly math book

I was traveling for two weeks so that's why this blog has been quiet... but now I'm back with tons of emails to go through and so.

One of them had an interesting link:


Math Doesn't Suck - a book whose cover looks like a girl magazine, but inside it should be solid fractions, percents, ratios and similar middle school math topics.

It's written in a "girly" style to middle school age girls, by the actress Danica McKellar (best known as Winnie Cooper in "The Wonder Years", inspiring them with the idea that math is not far from girls' life and activities. The book includes mentions of baking cookies, fashion, makeup, and such girly topics.

She wants to encourage girls to study math so that more of them would take it in college. But the problem is so many start dropping out and getting behind during the middle school years, and especially because of not understanding fractions and related topics.

You can read an interview of the author here and another good one here.

Disclaimer: I haven't read this myself. Some might not like it because of the style; talking about makeup, fashion, cheer leading and others. See some discussion about that here — the book sure has created controversy. I personally might have to be selective and careful, if I was using it with my daughters.

Rabu, 25 Juli 2007

Math Mammoth in French, too

It's a work in process, but recently I've had my Blue Series math books translated into French.

First one is available to purchase as of today, at HomeschoolEstore: Mammouth Mathématiques Addition 1 and more will be coming soon.

If you know how or where, please spread the word to Canadian homeschoolers who might be interested — I really don't know how to reach/find them myself.

Senin, 23 Juli 2007

Math enrichment problems at MathNotations

Today I want to highlight a blog called Math Notations by Dave Marain that specializes in math enrichment problems such as various type challenges and investigations. And they are quite good!


For example, recently Dave posted a geometry problem, and even gave the answer in his post, but he asked the readers to find DIFFERENT ways to solve the problem.

I encourage you to go see the problem and see how many different ways you can find to solve it!

That is exactly what we can ask students too - especially if you have many students and some of them solve the original problem in no time. You can use the same problem as a basis for further investigations for them.

His blog has "labels" in the sidebar, which makes it easy to find problems on a particular topic or concept.

Kamis, 19 Juli 2007

Review of Carnegie Learning's Cognitive Tutor Algebra 1

I've written one more review... This time it is about Carnegie Learning's Cognitive Tutor Algebra 1 curriculum.

Carnegie Learning's Algebra 1 curriculum is a unique algebra curriculum — unlike anything I've seen before. It is sure to appeal to some of you homeschoolers. I liked it quite a bit.

The curriculum consists of two parts: textbook and software.

The software component is called Cognitive Tutor. It provides the student intelligent computerized practice with everything in Algebra 1 curriculum.

The textbook also is somewhat different from your standard textbooks in the fact that often the whole lesson can be based on an exploration or investigation.

Read more here - you will also see screenshots and sample pages, pricing, an even a discount coupon code.

Senin, 16 Juli 2007

HomeschoolEstore name competition

HomeschoolEstore (homeschool - e - store) has launched a competition for a new name. They say people misspell it and just don't "get" the current name easily.

It is a store selling electronic downloadable products only, and often has new books, unit studies, etc. available. I have my books there too.

There are several prizes, so if you feel like getting creative, read the contest rules here.

Minggu, 15 Juli 2007

Homeschool Wisdom: 40 Tried and True Tips

From Sprittibee:

"I have gathered up a few morsels of advice from many different sources. Probably half of these originated with someone other than me... but they are all true... and all of them need repeating (especially to those who might not have heard them before)."

Read the 40 pieces of homeschool wisdom - I enjoyed them, you might too!

A question on MathScore

Hi Maria - I am really enjoying your workbooks for the kids - I can't wait to get going on fractions.

I wanted to ask you do you see value in any of the online math practice programs for drill? I saw that HS Buyers Co-op is offering www.mathscore.com - at a discount and we are trying it out on trial - It's just pretty much basic drill for speed and accuracy. I don't want to waste the $$ on it - if that is not really important to math.
Thanks for any feedback.

I've personally visited and even reviewed Mathscore. Mathscore is not just about basic drill on addition or multiplication - they have basic word problems, geometry, etc. as well. It is more like a math practice system for any kind of basic problems.

Kids do need to learn their facts by memory. So "drill" is not bad in itself.

Obviously math instruction should not be only drill. You should just balance it all. Teach concepts, teach why something works, let them practice, and help them master their facts. Drill can be part of that whole package. Just don't rely on it.

For example, if you subscribe to MathScore, you could teach your kids a "normal" math lesson on one day, and the next day let them practice at MathScore. It is a tool, it can be very useful, but it is not essential if they get to do math problems some other way. Just try it out and see if the kids like it, but don't forget basic instruction on concepts.

My review
MathScore - direct link
Info on the discount at Homeschool Buyers Co-Op.

Kamis, 12 Juli 2007

Math Mammoth Algebra 1 worksheets

News that some of you have been waiting for!

I've completed the Math Mammoth Algebra 1-A and 1-B worksheets collections. These worksheets cover all the topics in a typical algebra 1 course. Problems are again very varied.

The collection is designed to be used by teachers and tutors. It is not a text that explains algebra — it is a collection of worksheets or a workbook. But if you already have a textbook, the worksheets can supplement and provide extra practice, no matter what algebra program you're using.

Prices: Algebra 1-A is $6.50, 1-B is $5.50, answer keys $2 each. You can get both A and B plus their answer keys for $11.50.

Here are links to the sample worksheets:

1-A Contents
Variables and Expressions
Writing Equations
Rules With Subtraction
Ratios and Proportions
Explore Graphs of Linear Equations
Parallel and Perpendicular Lines
Compound Inequalities Involving 'And'
Solving Linear Systems by Elimination

1-B Contents
Multiplying Powers
Special Products
Solving Quadratic Equations by Finding Square Roots
Applications of Quadratic Equations
Add and Subtract Rational Expressions with Unlike Denominators
More Radical Equations
Geometry Problems


Please click here for more info — or buy the collection at Kagi store.

Sabtu, 07 Juli 2007

HippoCampus

I just found out about this site yesterday, and it might be worth your while knowing about it, too.

HippoCampus.org has free online multimedia lessons for high school and college level.

The topics include algebra, introductory and intermediate calculus, physics, history, biology, and a few other subjects as well.

This whole project is supported by The William and Flora Hewlett Foundation, and is free to use for general public.

I've seen several similar commercial services, so was surprised to see one that's free. It takes a lot of effort to make these interactive lessons, I would think.

Anyway, enjoy if it's your algebra or calculus time in math.

Senin, 25 Juni 2007

New Math Mammoth books: Clock, Money, and Measuring

Finally the time has come, and I can announce that there are THREE new books for my Math Mammoth Blue Series:

Math Mammoth Clock - about telling time, for grades 1-3. Price: $3.50.

Math Mammoth Money - counting coins, making change, simple money problems. For grades 1-3. Price: $3.

Math Mammoth Measuring - getting familiar with common measuring units for length, weight, and volume. Includes lots of hands-on problems. Mostly for grades 2 and 3. Price: $4.

As usual you can find some sample pages, table of contents, and more info on each book's web page.

The Blue Series and the All Inclusive packages have been updated, accordingly.

Kamis, 21 Juni 2007

Reflecting back - planning ahead

You might or might not be taking a break from school for summer. I know one family where the child does schoolwork 3 weeks, then is 1 week off, all year long. But many follow loosely the typical school year and will soon be off school for a while.

And this break time is a good time to reflect back on the past school year, past instruction, and also to plan ahead.

You know, I always encourage parents and teachers to see math instruction as a set of concepts, skills, and topics that you wish your student to master before some set point in time, instead of seeing it as "a book for this grade" or "these pages". You might still use a book or books, but study the book so you know which are the main topics in the book.

The "set point in time" does not have to be the end of a school year, either. Of course many homeschoolers realize this.

So what kind of concepts have your student or students studied this past year? Which ones are mastered? Which ones still need more practice?

A very big part of the elementary math (years 1-5) can be summarized in the fact that the children are learning the four operations addition, subtraction, multiplication, and division:

1) first with whole numbers
2) then with fractions
3) and with decimals.

Four operations, three kinds of numbers. Of course whole numbers in reality are decimals, but kids have to first start learning with whole numbers.

So this boils down to four operations, and two kinds of numbers. It's arithmetic, the art of calculating.

All in all, it's not that much material. It might seem like a lot, since it takes 5-6 years to cover, but in actual substance it is not that much. A lot of the topics get repeated a lot over the grades.

On grade 6 on, we also start encountering topics such as ratio, proportion, and percent — and two more operations: exponentiation and a tiny bit of square roots. Of course geometry and measuring topics are present on all grades.

You might want to glance over this chart again (I've posted this before):

math scope and sequence chart
(click to show larger image)

Consider where your child is at, and where you're going from now.

If you are planning to buy a math curriculum, or wish to find free curriculum materials, check the homeschool math curriculum resources section on my site. You will find reviews, plus these articles:

How to choose a homeschool math curriculum

Is your math curriculum coherent and logical?

Scope and sequence chart suggestion

Free and inexpensive curriculum materials - this is a list of materials that you can use to supplement, or in a pinch even for a complete curriculum if you plan it well.

The State of State Standards - an article rating the various states' mathematics standards and explaining the reasons why most states' standards are "substandard". Only three states got an "A" in this review.

Sabtu, 09 Juni 2007

Summer school program

I was sent this link about an online summer program for kids who're entering 3rd, 4th, or 5th grade next fall.

It uses daily interactive worksheets that you can also print out, if desired.

Right now the registration is FREE. The program starts on 11th of June.

See more at Stay Ahead! - Interactive Online summer math program.

An island of rationality in the insanity of math wars

That is the description of a new blog called Rational Mathematics Education, by Michael Paul Goldenberg.

I mention it for the sake of those of you who are interested in the trends in mathematics education, and the "math wards" between the traditional and the reform.
"The 'Net is flooded with videos, blogs, and what I view as hate lists and web sites all attacking progressive reform methods, tools, technologies, pedagogies and, most especially, text books in mathematics (although the onslaught against progressive science education is on its way, and the current focus on mathematics education reform was preceded by the still on-going war against "whole language" and related ideas in literacy education.

This blog has been created to provide direct replies to entries on other blogs where the blogger invites feedback but refuses to post negative responses, critical comments, uncomfortable questions, etc., of ANY kind, regardless of how polite they may be. What do such people fear, I wonder?"



As for me, I'm just real real busy trying to finish up the Math Mammoth complete curriculum for 3rd grade, and get that to the folks at Winterpromise. So that's why there has been sort of a break in blogging. I'll try to do better after that's all done.

Jumat, 01 Juni 2007

Statistics worksheets

After some delay the Statistics Worksheets Collcetion from the Math Mammoth Green Series is now available. It is priced at $4 for 47 worksheets.

The sheets span about five grade levels (from grade 3 to 7); however the majority are for grades 5-7.

In this collection, the worksheets are organized by topic (see table of contents). Within each topic, the difficulty level varies because the sheets have originally been made for different grade levels. Thus the teacher can choose a sheet of right difficulty level, or even assign some students easier sheets and some students more challenging ones, on the same topic.

Math Mammoth Statistics Worksheets Collection covers bar graphs, line graphs, circle graphs - both reading and drawing them - data analysis, mean, median, and mode, box-and-whisker plots, stem-and-leaf plots, measures of variation, misleading statistics, data gathering, and a few statistics projects. I hope the problems will fit your needs!

Selasa, 29 Mei 2007

Goodies for teachers and all

Just a few items of interest:

1) Math Goodies CD from www.MathGoodies.com has been updated earlier this year; I got to see it, and updated my review of the CD. It's full of good math lessons with interactive exercises, printable worksheets, crossword puzzles and more.

2) I've added a free online equation editor to my site. This would be most useful for teachers or others who write math content and need images for complex symbols and math expressions.

3) Those of us who use math a lot might also enjoy a free calculator/graphing program called SpeQ Mathematics. You can type complex expressions into it, define variables to be used in later calculations, and make plots.

Rabu, 16 Mei 2007

Mnemonic helps for multiplication tables?

...regarding my third grader. We are still slogging through learning the times tables. To liven it up, I decided to order Times Tales (I ordered the deluxe version that includes division as well).

I have read different opinions about using mnemonic devices to learn math facts. Some say that mnemonic devices actually slow the student down, and one even went as far to say it was like counting on fingers. I don't want to use Times Tales if it's going to slow her down, and I do want to make sure she knows her math facts cold.

I, myself, remember I didn't know 8x8=64 in seventh grade, and I just figured it in my head, 8+8=16, 16+16=32, 32+32=64 -- 8x8=64. I did this until I realized how slow I was and decided to commit the facts I didn't know to memory. What do you think about Times Tales and other "helps" for math facts?


Mnemonic helps in themselves are not bad. We use them all the time, in everyday life situations. You have a phone number, you divide it to 2-digit numbers, maybe remember it has successive numbers, or doubles, etc.

I once memorized a certain 4-digit pin number by dividing it to two 2-digit numbers, and remembering that the latter was 9 less than the first... but after a while I remembered it without that.

On Times Tales. It's a fine program in itself. It associates a silly story and picture with each "difficult" upper times tables fact. You've probably seen samples. I don't think it is going to hinder... Basically, if it works for your kid, let's say you will show 8 x 7 to your your kid. He will see 8 x 7 and suddenly also see the silly picture of lady eight and the character 7 driving in a car, in his mind, and remember "It's 56."

It's not too much different from using a rhyme such as "5, 6, 7, 8, fifty-six is seven times 8."

Such a program can be a confidence booster as well.

Now, for some kids it doesn't work because they don't easily remember silly stories, and then it can cause frustration. Or, they're older and don't enjoy the silly stories anymore.

All these "helps" are fine in their place, but you have to be sensitive to your child so that the mnemonic "help" does not end up being an additional burden in itself... such as if the child cannot easily remember the stories or the song or whatever the "help" is.

So it's totally up to you. Try it first with the free sample they offer on their website... and see how your child reacts.

That program is an additional resource of course, and doesn't replace studying multiplication concept itself.
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