Q&A #19603

Patterns in multiplying by 0 and 1

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From: Gail (for Teacher2Teacher Service)
Date: May 25, 2008 at 07:51:02
Subject: Re: Patterns in multiplying by 0 and 1

Hi! Thanks for asking us this question. I find that a good way to get my students to learn about patterns in numbers is to let them discover them. You might set up a series of multiplication problems in which one factor is 0, and then let students use a calculator to find the products. Be sure to put the 0 in different places (first, last, somewhere in the middle of several factors), so your students will figure out that it doesn't matter if you are multiplying 2 x 0 or 0 x 7 or 0 x 24, or even 3 x 4 x 8 x 0 x 9 x 2, the product will always be 0. You can do the same sort of thing with 1 as a factor. Again, be sure to move the factor around, 1 x 5, 6 x 1, 83 x 1, etc. I think I wouldn’t share a problem like 4 x 1 x 7 x 3 yet, though. The idea here is to set up problems that will lead your students to find out what happens when they multiply by 0 and 1, then let them state the “rule”. It will make it their rule, and they will remember it much better. You might even consider naming it after the person who “discovered” it to be true; it could be TiQuan’s Rule. Later you could mention that it has another name as well, and is considered a property of numbers. -Gail, for the T2T service

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