1

1. Positive and
Negative
Numbers
Created by Richard Bull

2. Definition
• Positive number – a number
greater than zero.
0 1 2 3 4 5 6

3. Definition
• Negative number – a number
less than zero.
0 1 2 3 4 5 6-1-2-3-4-5-6

4. Negative Numbers Are Used to
Measure Temperature

5. Negative Numbers Are Used to Show
Debt
If you get a loan from the bank for £5,000.
If you were to look at your bank balance it
would show -£5,000.

6. Negative Numbers Are Used to
Measure Under Sea Level
0
10
20
30
-10
-20
-30
-40

7. Hint
• If you don’t see a negative or
positive sign in front of a
number it is positive.
9+

8. Integer Addition Rules
Rule #1
•If the signs are the same, pretend the signs aren’t there
and add them.
-9 + -5 = 14
Rule #2
•Ask which absolute number is bigger
•now remember what sign it was, this is the sign for your
answer
-

9. Solve the Problems
• -3 + -5 =
• 4 + 7 =
• -6 + -7 =
• 5 + 9 =
• -9 + -9 =
-8
-18
14
-13
11

10. Integer Addition Rules
Rule #2
•If the signs are different,
3 + -5 =
pretend the signs aren’t there and subtract the smaller
absolute number from the larger absolute number
5 - 3 = 2
Now look back at the original question and use
the sign of the biggest absolute number for your
answer
3 + -5 =
-

11. Solve These Problems
•3 + -5 =
•-4 + 7 =
•(+3) + (-4) =
•-6 + 7 =
•5 + -9 =
•-9 + 9 =
-25 – 3 = 2
0
-4
1
-1
3
9 – 9 = 0
9 – 5 = 4
7 – 6 = 1
4 – 3 = 1
7 – 4 = 3

12. One Way to Add Integers Is With a
Number Line
0 1 2 3 4 5 6-1-2-3-4-5-6
When the number is positive count
to the right.
When the number is negative count
to the left.
+-

13. One Way to Add Integers Is With a
Number Line
0 1 2 3 4 5 6-1-2-3-4-5-6
+
-
+3 + -5 = -2

14. One Way to Add Integers Is With a
Number Line
0 1 2 3 4 5 6-1-2-3-4-5-6
+
-
+6 + -4 = +2

15. One Way to Add Integers Is With a
Number Line
0 1 2 3 4 5 6-1-2-3-4-5-6
+
-
+3 + -7 = -4

16. One Way to Add Integers Is With a
Number Line
0 1 2 3 4 5 6-1-2-3-4-5-6
-
+
-3 + +7 = +4

17. One Way to Add Integers Is With a
Number Line
0 1 2 3 4 5 6-1-2-3-4-5-6
-
+
-5 + +3 = +4

18. One Way to Add Integers Is With a
Number Line
0 1 2 3 4 5 6-1-2-3-4-5-6
-
+
-2 + +8 = +6

19. One Way to Add Integers Is With a
Number Line
0 1 2 3 4 5 6-1-2-3-4-5-6
-
+
-5 + +2 = -3

20. One Way to Add Integers Is With a
Number Line
0 1 2 3 4 5 6-1-2-3-4-5-6
-
-
-4 + -2 = -6

21. One Way to Add Integers Is With a
Number Line
0 1 2 3 4 5 6-1-2-3-4-5-6
-
-
-2 + -3 = -5

22. One Way to Add Integers Is With a
Number Line
0 1 2 3 4 5 6-1-2-3-4-5-6
-
-
-1 + -4 = -5

23. One Way to Add Integers Is With a
Number Line
0 1 2 3 4 5 6-1-2-3-4-5-6
-
-
-4 + -1 = -5

24. One Way to Add Integers Is With a
Number Line
0 1 2 3 4 5 6-1-2-3-4-5-6
+
+
4 + 1 = 5

25. One Way to Add Integers Is With a
Number Line
0 1 2 3 4 5 6-1-2-3-4-5-6
+
+
3 + 2 = 5

26. One Way to Add Integers Is With a
Number Line
0 1 2 3 4 5 6-1-2-3-4-5-6
+
+
1 + 5 = 6

27. Add integers with same signs:
Add the numbers and keep the sign
a)3 + 2 = 5 b) -4 + (-6) = -10
Add integers with different signs:
Subtract the (absolute values) and keep the sign of the sign
of the absolute value
a) -7 + 4 = -3 b) 1 + (-9) = -8
Created by Richard Bull