1. Subtracting Integers

2. Warm Up 1.71 – 15 =2. 71 + (-15) = 3.53 – 45 =4. 53 + (-45) = 5.79 – 79 =6. 79 + (-79) = 7.Do you notice anything about these exercises? Explain your observation thoroughly.

3. Modeling Integer Subtraction + – You can use colored counters (or positive and negative symbols) to model adding integers with different signs. In some cases, you may need to add zero pairs. One positive and one negative form a zero pair.

5. If we model -4 – 7 using counters, do we need to add zero pairs? Explain.

6. Subtracting on a Number Line To model the difference 5 – 3 on a number line, you start at 5 and move 3 units to the left. Notice that you model the sum 5 + (-3) in the same way. Subtracting 3 is the same as adding its opposite, -3. You can use the fact that subtracting a number is the same as adding its opposite to find the difference of two integers.

8. Which Way? The arrow points right if you are adding a positive number because positive numbers increase as you move to the right of zero. The arrow points left if you are adding a negative number because negative numbers decrease as you move to the left of zero.

9. How do we find 5 – (-8) on a number line? How do we find 5 – (-8) using counters? Do we get the same results?

10. Subtracting Integers by Adding the Opposite

11. The temperature fell from -2◦C to -10◦C. Predict whether the change in temperature would be positive or negative. Then subtract to find the change.

12. 1.-7 – 2 = 2.3 – 5 = 3.-1 – (-3) = 4.-8 – (-4) =