Q&A #16511

Modeling Subtraction of Integers using Red and Yellow Counters

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From: Gail (for Teacher2Teacher Service)
Date: Jan 15, 2006 at 01:17:16
Subject: Re: Modeling Subtraction of Integers using Red and Yellow Counters

Hi Mimi, I agree with Jeanne that the best way to do this is to begin by having your students learn about "zero pairs". I use tile spacers, too. I also use two color counters, and number lines. with the two color counters you can show zero pairs by having the same number of red and yellow counters. They can be paired up, and each set of two makes a "zero pair". On a number line, use arrows to show the distance and direction traveled. A zero pair on a number line is made when the two arrows are the same length, but go in opposite directions. For example, one arrow starts at 10 and goes to 3, another arrow starts at 3 and goes to 10. Or, one arrow starts at -2 and ends at 4. Another arrow starts at 4 and ends at -2. These are zero pairs because where you started is where you end up. It is like you didn't go anywhere. It is really important that you use more than one model when working with integers. Your students will be more likely to make strong generalizations about the rules for working with integers if they have a variety of methods to think about. Also, some students will be more comfortable with one model than another, so showing a variety will give everyone a chance to understand. I hope this is helpful to you, -Gail, for the T2T service

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