A quite long prime

Mathematicians at UCLA have verified now the largest known prime number, 13 million digits long!

It's a Mersenne prime, in the form 2^p − 1. This new prime is 2^43,112,609 − 1. (And no, you can't put it in your calculator and get an answer... )

Read the news story

This kind of prime hunting requires a network of computers running together to do the massive amounts of calculations.

Credit card math

Considering the crisis taking place within U.S. financial institutions, it's a good reminder of how we MUST teach our kids how to work out the math with credit cards, mortgages, and any type of loans.

Murray Bourne from squareCircleZ has taken this matter to heart and has written a good lesson about math that goes into taking a loan. He's also analyzed several misleading credit card ads and figured out the TRUE interest rate (which you find out after reading the fine print).

First go here:

Credit Cards - a simplified discussion on how banks make money on credit cards. This is a must read for all people (young or old) who even consider taking a credit.

Then check these posts and warn your youngsters:

Misleading Credit Card Advertising. This ad advertises "a attractive interest rate of 5% p.a." (p.a. means per annum or yearly interest rate), but has a "small" administration fee of 6%.

And then check another misleading credit card ad which advertises a 0% p.a.*. Notice it has an asterisk... and the info in the asterisk can lead up to 24% annual interest!

Two new books in the Blue Series

64 pages
(of which 37 are lesson pages)
Price: $2.50 download

Buy at Kagi (PDF download)

Sample pages (PDF)

Contents and Introduction
Shapes
Right Angles
Line Symmetry
Perimeter
Solids

1. Math Mammoth Early Geometry covers geometry topics for the early elementary grades (approximately grades 1-3).

The first lessons in this book have to do with shapes - that is where geometry starts. Children learn the names of the common shapes, and also put several shapes together to form new ones, or divide an existing shape into new ones. They practice using a ruler to draw various shapes and are introduced to tilings.

Next children learn the concepts of parallel lines and lines that are at a right angle (perpendicular lines). The book also has beginner lessons about symmetry, area, perimeter, and solids.

After studying these early geometry lessons, you can continue the study of geometry with Math Mammoth Geometry 1 book. In it, children will learn to classify figures (during grades 4-6) according to their sides and angles, and learn much more about area, perimeter, and volume.

52 pages
(of which 40 are lesson pages)
Price: $3.00 PDF download



Sample pages (PDF)
Contents
Counting One, Two,and Five-Cent Coins
Counting Coins Review
Euros, part 2
Practising Shopping
Mental Math and Money Problems

2. Math Mammoth European Money is a worktext that covers money-related topics usually encountered during grades 1-3. The book contains both textbook explanations and exercises, and is designed to be very easy to teach from, requiring very little teacher preparation (you do need to find practice coins before the
lessons).

The book starts with first-grade topics such as counting coins with cent-amounts and easy problems about
change.

From there, the lessons advance toward second-grade, and finally to third grade topics, such as practicing with euro amounts, and figuring out total bills and change. Therefore, you can also let your child work the pages of this book in different time periods, and not go through it all at once, depending on your child's
current level.