1. Adding Integers
Using a Number Line

2. You start at the origin or zero.
Adding Integers
You start at the origin or zero.
Positive numbers move to the right.
Negative numbers move to the left.
Origin
(Start) -6 -5 -4 -3 -2 -1 1 2 3 4 5 6

3. Adding Integers
= -2
-4 + 2
Start at the origin and move to -4
Then move to +2
Where you finish is your answer
Origin
(Start) -6 -5 -4 -3 -2 -1 1 2 3 4 5 6 -4 +2

4. -4 + 2 = -2 Negative = Down Positive = Up
Adding Integers
Integer
Elevator 8 7 6 5 4 3 2 1 -1 -2 -3 -4 -5 -6 -7 -8 = -2
Negative = Down
Positive = Up
Elevator
Entrance
Using a vertical number line is easier to relate to since most of us have been in an elevator! -4 +2

5. Adding Integers
Integer
Elevator 8 7 6 5 4 3 2 1 -1 -2 -3 -4 -5 -6 -7 -8
Watch the direction of the elevator when we do integer problems with the SAME SIGN!
Elevator
Entrance

6. Adding Integers 8 1) +3 + 5 = +5 +3 Integer Elevator 8 7 6 5 4 3 2 1-1 -2 -3 -4 -5 -6 -7 -8
1) = 8 +5 +3
Elevator
Entrance

7. Adding Integers 8 5 1) +3 + 5 = 2) +1 + 4 = +4 +1 Integer Elevator 8 76 5 4 3 2 1 -1 -2 -3 -4 -5 -6 -7 -8
1) = 8
2) = 5 +4 +1
Elevator
Entrance

8. Adding Integers 8 5 -5 1) +3 + 5 = 2) +1 + 4 = 3) -2 - 3 = -2 -3
Elevator 8 7 6 5 4 3 2 1 -1 -2 -3 -4 -5 -6 -7 -8
1) = 8
2) = 5
3) = -5
Elevator
Entrance -2 -3

9. What do you notice about the direction of the integer elevator?
Adding Integers
Integer
Elevator 8 7 6 5 4 3 2 1 -1 -2 -3 -4 -5 -6 -7 -8
What do you notice about the direction of the integer elevator?
1) = 8
2) = 5
3) = -5
Elevator
Entrance
4) = -7 -3 -4

10. A positive plus a positive travels up up.
Adding Integers
Integer
Elevator 8 7 6 5 4 3 2 1 -1 -2 -3 -4 -5 -6 -7 -8
1) = 8
A positive plus a positive travels up up.
2) = 5
3) = -5
A negative plus a negative travels down down.
Elevator
Entrance
4) = -7 -5
5) = +8 -1
6) = -6

11. Both signs are the same so you end up traveling the same direction. 5
Adding Integers
Integer
Elevator 8 7 6 5 4 3 2 1 -1 -2 -3 -4 -5 -6 -7 -8
1) = 8
Both signs are the same so you end up traveling the same direction.
2) = 5
3) = -5
Elevator
Entrance
4) = -7 -5
5) = +8 -1
6) = -6

12. Describe an easy way to add these integers?
Adding Integers
Integer
Elevator 8 7 6 5 4 3 2 1 -1 -2 -3 -4 -5 -6 -7 -8
Describe an easy way to add these integers?
When the signs are the same and you are adding,
just add the numbers and the sign stays the same.
Elevator
Entrance

13. Adding Integers
Integer
Elevator 8 7 6 5 4 3 2 1 -1 -2 -3 -4 -5 -6 -7 -8
Watch the direction of the elevator when we do integer problems with the DIFFERENT SIGNS!
Elevator
Entrance

14. Adding Integers 2 1) -3 + 5 = +5 -3 Integer Elevator 8 7 6 5 4 3 2 1-1 -2 -3 -4 -5 -6 -7 -8
1) = 2
Elevator
Entrance +5 -3

15. Adding Integers 2 -4 1) -3 + 5 = 2) -5 + 1 = -5 +1 Integer Elevator 87 6 5 4 3 2 1 -1 -2 -3 -4 -5 -6 -7 -8
1) = 2
2) = -4
Elevator
Entrance -5 +1

16. Adding Integers 2 -4 -2 1) -3 + 5 = 2) -5 + 1 = 3) +2 + - 4 = +2 -4
Elevator 8 7 6 5 4 3 2 1 -1 -2 -3 -4 -5 -6 -7 -8
1) = 2
2) = -4
3) = -2 +2
Elevator
Entrance -4

17. Adding Integers 2 -4 -2 5 1) -3 + 5 = -3 2) -5 + 1 = +8 3) +2 - 4 =
Elevator 8 7 6 5 4 3 2 1 -1 -2 -3 -4 -5 -6 -7 -8
1) = 2 -3
2) = -4 +8
3) = -2
4) = 5
Elevator
Entrance

18. Adding Integers 2 -4 -2 5 1) -3 + 5 = 2) -5 + 1 = 3) +2 - 4 = -4 +4
Elevator 8 7 6 5 4 3 2 1 -1 -2 -3 -4 -5 -6 -7 -8
1) = 2
2) = -4
3) = -2 +4 -4
4) = 5
Elevator
Entrance
5) =

19. What do you notice about the direction of the integer elevator?
Adding Integers
Integer
Elevator 8 7 6 5 4 3 2 1 -1 -2 -3 -4 -5 -6 -7 -8
1) = 2
What do you notice about the direction of the integer elevator?
2) = -4
3) = -2
4) = 5
Elevator
Entrance
5) = -6
6) = -3 +3

20. A positive plus a negative travels up then down . 2
Adding Integers
A positive plus a negative travels up then down .
Integer
Elevator 8 7 6 5 4 3 2 1 -1 -2 -3 -4 -5 -6 -7 -8
1) = 2
2) = -4
3) = -2
4) = 5
Elevator
Entrance
A negative plus a positive travels down then up.
5) = -6
6) = -3 +3

21. Adding Integers
Integer
Elevator 8 7 6 5 4 3 2 1 -1 -2 -3 -4 -5 -6 -7 -8
1) = 2
NOTICE: The integer elevator is moving in different directions because both numbers are different!
2) = -4
3) = -2
4) = 5
Elevator
Entrance
5) = -6
6) = -3 +3

22. Describe an easy way to add these integers?
Adding Integers
Integer
Elevator 8 7 6 5 4 3 2 1 -1 -2 -3 -4 -5 -6 -7 -8
Describe an easy way to add these integers?
When the signs are the different and you are adding,
just subtract the numbers and the larger number determines the sign.
Elevator
Entrance

23. SIGNS ARE THE DIFFERENT = TAKE THE DIFFERENCE!
Adding Integers
SIGNS ARE THE DIFFERENT =
TAKE THE DIFFERENCE!
Integer
Elevator 8 7 6 5 4 3 2 1 -1 -2 -3 -4 -5 -6 -7 -8
When the signs are the different and you are adding,
just subtract the numbers and the larger number determines the sign.
Elevator
Entrance

24. Try These
3 -5 = = = =
5 -9 = =