1. Warm - Up Solve for the following: 4 + (-2) -12 + -13 -125 + 33
8 + (-47)
99 + (-34)
(-56) + 15

2. Balloons and Sandbags

3. When you add a balloon, Mr. Integer goes up by 1.8 7 6 5 4 3 2 1 -1 -2 -3
When you add a balloon, Mr. Integer goes up by 1. -4 -5 -6 -7 -8

4. When you add a sandbag, Mr. Integer goes down by 1.8 7 6 5 4 3 2 1 -1 -2 -3 -4
When you add a sandbag, Mr. Integer goes down by 1. -5 -6 -7 -8

5. Where will Mr. Integer be if we add 3 balloons?8 7 6 5 4 3 2 1 -1 -2 -3 -4 -5 -6 -7
Where will Mr. Integer be if we add 3 balloons? -8

6. Where will Mr. Integer be if we add 4 sandbags?8 7 6 5 4 3 2 1 -1 -2 -3 -4
Where will Mr. Integer be if we add 4 sandbags? -5 -6 -7 -8

7. Where will Mr. Integer be if we add 6 balloons?8 7 6 5 4 3 2 1 -1 -2 -3 -4 -5 -6 -7
Where will Mr. Integer be if we add 6 balloons? -8

8. Where will Mr. Integer be if we add 5 sandbags?8 7 6 5 4 3 2 1 -1 -2 -3 -4 -5 -6 -7
Where will Mr. Integer be if we add 5 sandbags? -8

9. What operation has Mr. Integer been modeling up to this point?
Mr. Integer has been modeling the addition of integers.
The balloons are positive integers
The Sandbags are negative

10. Where will Mr. Integer be if we remove 2 balloons?8 7 6 5 4 3 2 1 -1 -2 -3 -4
Where will Mr. Integer be if we remove 2 balloons? -5 -6 -7 -8

11. Where will Mr. Integer be if we remove 8 sandbags?7 6 5 4 3 2 1 -1 -2 -3 -4 -5 -6 -7 -8
Where will Mr. Integer be if we remove 8 sandbags?

12. Where will Mr. Integer be if we remove 5 balloons?8 7 6 5 4 3 2 1 -1 -2 -3 -4
Where will Mr. Integer be if we remove 5 balloons? -5 -6 -7 -8

13. Where will Mr. Integer be if we remove 5 sandbags?8 7 6 5 4 3 2 1 -1 -2 -3 -4 -5 -6 -7 -8

14. Where will Mr. Integer be if we remove 4 balloons?
-20
Where will Mr. Integer be if we remove 4 balloons?
-21
-22
-23
-24
-25
-26
-27
-28
-29
-30
-31
-32
-33
-34
-35
-36

15. Where will Mr. Integer be if we remove 13 sandbags?5 4
Where will Mr. Integer be if we remove 13 sandbags? 3 2 1 -1 -2 -3 -4 -5 -6 -7 -8 -9
-10
-11

16. Where will Mr. Integer be if we remove 9 balloons?2 1 -1 -2 -3 -4 -5 -6 -7 -8 -9
-10
Where will Mr. Integer be if we remove 9 balloons?
-11
-12
-13
-14

17. Where will Mr. Integer be if we remove 8 sandbags?
-15
-16
-17
-18
-19
-20
-21
-22
-23
-24
-25
-26
-27
-28
-29
-30
Where will Mr. Integer be if we remove 8 sandbags?
-31

18. Discussion
What happened to Mr. Integer when we took away the balloons?
Use that information to make a statement about the effect of subtracting a positive number.
What happened to Mr. Integer when we took away the sandbags?
Use that information to make a statement about the effect of subtracting a negative number.

19. Subtracting Integers
Think of Mr. Integer’s position on the number line as the first integer. Then figure what effect subtracting the 2nd integer has on Mr. Integer’s position.
(-3) – (-2)
10 – (-3)
15 – 3
(-12) – (-14)
(-40) – (-13)
5 – (-15)

20. In Summary Subtraction is the opposite of addition.
When you add a positive, your value increases.
When you subtract a positive, your value decreases.
When you add a negative, your value decreases.
When you subtract a negative, your value increases.