1. October 22, 2008
Teacher Notes
Subject: Maths
Topic: Number operations
Title: Addition of Integers
Year Group(s): 7, 8 and 9
Curriculum-related themes: Non-specific
Intended learning outcome(s)
· Learn the rules for adding integers
· Gain practice adding integers
Recommended usage: Introduction / main activity
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2. October 22, 2008
Addition of Integers
Windows(R) operating system and Mac OS X
operating system software
Submitted by: Gerry-Lynn Borys
Red Deer Catholic Regional Division: St.Patrick's
Community School
-10 -9 -8 -7 -6 -5 -4 -3 -2 -1 0 +1 +2 +3 +4 +5 +6 +7 +8 +9 +10

3. October 22, 2008
You can use algebra tiles to add integers.
means + 1
means -1

4. October 22, 2008
Example
=+1 = -2
This is the same as This is the same as saying
saying (+3) + (-2) = +1 (+2) + (-4) = -2

5. October 22, 2008
Zero principle
The zero principle states that when you add two
opposites, their sum is equal to zero.
(+1) + (-1) = 0

6. October 22, 2008
So, in our two examples
left with
left with -2
+1
=0 =0 =0 =0

7. October 22, 2008
Use the yellow (positive) tiles and red
(negative)tiles to add each pair of integers, then
write the addition sentence for each.
(+5) + (-4)
(+3) + (-7)
(-4) + (-3)

8. October 22, 2008
Answers
(+5) + (-4)
(+3) + (-7)
(-4) + (-3)

9. October 22, 2008
You can also use a number line to add integers.
+ sign means move forward or to the right of zero
- sign means move back or to the left of zero
(+3) + (-2) Start at +3 and move
back 2 spaces
-10 -9 -8 -7 -6 -5 -4 -3 -2 -1 0 +1 +2 +3 +4 +5 +6 +7 +8 +9 +10

10. October 22, 2008
Solve the following questions using the number line.
(-3) + (-2)
-10 -9 -8 -7 -6 -5 -4 -3 -2 -1 0 +1 +2 +3 +4 +5 +6 +7 +8 +9 +10
(+5 ) + (-6)
-10 -9 -8 -7 -6 -5 -4 -3 -2 -1 0 +1 +2 +3 +4 +5 +6 +7 +8 +9 +10
(-7) + (+4)
-10 -9 -8 -7 -6 -5 -4 -3 -2 -1 0 +1 +2 +3 +4 +5 +6 +7 +8 +9 +10

11. October 22, 2008
Answers
(-3) + (-2)
-10 -9 -8 -7 -6 -5 -4 -3 -2 -1 0 +1 +2 +3 +4 +5 +6 +7 +8 +9 +10
(+5 ) + (-6)
-10 -9 -8 -7 -6 -5 -4 -3 -2 -1 0 +1 +2 +3 +4 +5 +6 +7 +8 +9 +10
(-7) + (+4)
-10 -9 -8 -7 -6 -5 -4 -3 -2 -1 0 +1 +2 +3 +4 +5 +6 +7 +8 +9 +10

12. October 22, 2008
You can also add integers algebraically.
Simply ignore the addition sign and
do what the sign on the second
integer tells you to do.
Example (+4) + (-5)
Ignore the addition sign and this
question becomes
4 - 5 = -1

13. October 22, 2008

14. October 22, 2008

15. October 22, 2008

16. October 22, 2008
(+4) + (-3)= _____
+1
(-3) + (+6)= _____
+3
(+5) + (+2)= _____
+7
(-2) + (-5) = _____
-7
(-4) + (+2)= _____ -2