Tampilkan postingan dengan label manipulatives. Tampilkan semua postingan
Tampilkan postingan dengan label manipulatives. Tampilkan semua postingan

Kamis, 03 Maret 2011

The value of manipulatives

(Note: I'm "resurrecting" an old post, with added information and a video. The topic is still very much valid.)

Manipulatives are IN, in math education. But do they TRULY facilitate learning to such an extent as people promoting them claim?

The entry at Text Savvy, Hands-on, Brains-Off, explains some of the pitfalls in manipulative use. Very enlightening!

Quoting from an article at Education Week (Studies Find That Use of Learning Toys Can Backfire):
In a similar series of experiments at the elementary-school level, the researchers found that children taught to do two-digit subtraction by the traditional written method performed just as well as children who used a commercially available set of manipulatives made up of individual blocks that could be interlocked to form units of 10.

Later on, though, the children who used the toys had trouble transferring their knowledge to paper-and-pencil representations. Mr. Uttal and his colleagues also found that the hands-on lessons took three times as long as the traditional teaching methods did.

The video below also illustrates how manipulative use can lead to problems.

The girl solves an addition problem involving thousands by drawing thousand-blocks, hundred-sheets, etc. on the board, taking 8 minutes. Then she says that at home she has been taught to stack the numbers and add. She solves it that way, too, taking 1 minute. But she gets two different answers.

(Hat tip to Denise)



Clearly, manipulatives aren't the best way to solve such problems, and children shouldn't be led to believe so. Not that this girl believed that way... she seems to understand which way is easier and quicker.

My take is that manipulatives aren't the ultimate answer to math teaching.

They're a reasonable starting point. But children should NOT be taught to rely on them. Children need to be taught and shown how to transfer all of that concrete play into the abstract.

In my books, I often instruct concepts with pictures, which essentially take the place of manipulatives. Then the student does a bunch of problems that have the same pictorial representation in them, including having to draw  those same pictorial models to illustrate the math problems. THEN after that, the student goes on to totally abstract representation.

Here's one example from my book Add & Subtract 2-B: Adding with Whole Tens. The student first adds using the pictorial model, and then with numbers only.

I don't know if that approach suffers from the drawbacks mentioned in the article above. I hope not; from the feedback I get, it seems to work well.

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

Kamis, 10 Mei 2007

Basic abacus as a manipulative

abacus
I don't want to leave out one of the best manipulatives there is for grades 1-2: a simple "school" abacus that has 10 wires and 10 beads on each wire.

I'm not talking about a Chinese or Japanese abacus with a special counting system. I'm talking about using a simple 100-bead abacus for counting, and treating each bead as 1. You don't have to learn any of these sophisticated systems that have been in use with various abacuses. Just consider each bead being 1, period.

Then you have 10 tens, or a hundred, in your abacus, and that goes a long way explaining tens and ones or 2-digit place value to first graders.

To help a child learn the numbers up to 100, you can play a simple game with the abacus. When it's your turn, you say a number, and the child "makes" it or shows it on the abacus. Then your child says a number for you to show on the abacus.
You can also show the child other things, such as how the subtractions
10 − 5
20 − 5
60 − 5
are similar, or let the student find sums of 2-digit numbers, such as 23 + 45. He can move 2 tens and 4 tens, then 3 and 5 individual pieces — you can show how to add the tens and ones separately.

You can let the child explore what happens with 28 + 9.

It's better if the abacus has the first five beads colored differently from the next five, in each row, like in this silly picture.

Then the child will easily recognize 6, 7, and 8 beads without counting. Also, let's say you choose 6 beads on one wire and 8 on the next one. You can show how the five and five on those two wires makes ten, and some are left over.

You can also model multiplication: move 4 beads on each of the 5 neighboring wires, and there you have 5 times 4!

So this is not rocket science; it is very easy. You don't need to learn any special abacus systems.

Here's a picture of an old school abacus.

Wikipedia has info on all different kinds of abaci, including this kind of usage of the school abacus.

You can browse Amazon's abacus selection here.

Selasa, 01 Mei 2007

The good side of manipulatives

Update: read also Mama Squirrel's excellent blogpost on the issue; basically there is probably a balance in this, as in everything.



If you haven't, go pay a visit to the National Library of Virtual Manipulatives.

Lots of good stuff there!

So, why would I suddenly turn around and praise manipulatives, if I just mentioned how they're not the "ultimate thing" in math education?

It's just one of those things that can be good, if used right, in its rightful place.

Manipulatives do help students to understand concepts, initially, on a concrete level. But they shouldn't stop there. Kids need to learn to make generalizations. That is where the power of mathematics is.

For example, maybe you'd use The Base Blocks Addition to illustrate the concept of "carrying" to tens and hundreds (or "trading") in addition.

Once the student understands that, they should be able to translate their knowledge into bigger and smaller place values (including decimal addition).

So it's the age-old truth; there is balance in everything.

Or, what do you think?
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