Modeling Integer Operations

In this blog post we are going to show you how to add, subtract, multiply and divide integers.

Addition

6 +  -4  = 2

For addition, we first put down 6 positive chips to show the first part of the equation. Then, we place 4 negative chips to show the second part of the equation. We put the negative chips underneath the positive chips to make 4 zero pairs which gives us 2 as the answer.

Subtraction

4 -  -3  = 7

For subtraction, you first have to place 4 positive chips. Then, you have to add 3 zero pairs which still makes the total of the 4. Next, you have to subtract -3 from 4, or 3 -3 chips, which makes positive 7 as the answer.

Multiplication

-4 * -2  = 8

For multiplication, you first want to make 4 groups, but instead of -2 in each group, you want to put 2 zero pairs in each group. You do this so that you have groups to take away. Then, you want to take away 4 groups of negative 4 to get positive 8 as your answer.

Division

-84 = -2

For division, you first have to get 8 negative chips. Once you got your chips, you want to divide the chips into 4 equal groups since the equation is -84. Then, you count up however many negative chips are in each group to get -2 chips as the answer.

Rules for adding, subtracting, multiplying and dividing integers: (Clearly explain the rules as you understand them here. Use math language.)

Negative plus Positive; Positive/negative

Negative plus Negative; Negative

Positive plus Positive; Positive

Positive minus Positive; Positive

Negative minus Negative; Negative

Negative minus Positive; Negative

Positive minus Negative; Negative

Negative times Positive; Negative

Negative times Negative; Positive

Positive times Positive; Positive

Negative divided by Negative; Positive

Negative divided by Positive; Negative

Positive divided by positive; Positive