Mastering Subtraction with Integers on a Number Line

1. Subtracting Integers on a Number Line

2. How to subtract using a number line • Place a circle on the number line to represent the first number in the problem. • Since this is subtraction, the second number will tell you how much to take away. • This is the opposite of addition. • A positive second number means you should move to the left. • A negative second number means you should move to the right. • The number you end on is the answer.

3. Example 1 • Model 5 - 4 using a number line. • Start at 5 on the number line. • Take away 4, or move 4 spaces to the left since the second number is positive. – 4 5 - 4 = 1

4. Example 2 • Model 5 – 8 • Start at 5 on a number line. • Take away 8, or move 8 spaces to the left since the second number is positive. – 8 5 - 8 = -3

5. Example 3 • Model 5 – (-4) • Start at 5 on the number line. • Take away -4, or move 4 spaces to the right since the second number is negative. – (-4) 5 – (-4) = 9

6. Example 4 • Model -3 - 4 on a number line. – 4 -3 - 4 = -7

7. Example 5 • Model -1 - (-6) on a number line – (-6) -1 – (-6) = 5

8. Example 6 • Model 4 - 10 on a number line – 10 4 - 10 = -6

9. Example 7 • Model -8 - (-12) on a number line – (-12) -8 – (-12) = 4

10. Example 8 • Model -2 - 6 on a number line – 6 -2 - 6 = -8

11. Example 9 • Model 3 - (-4) on a number line – (-4) 3 – (-4) = 7

12. Example 10 • Model -7 – (-7) on a number line – (-7) -7 – (-7) = 0