-20
-15
-10
-5
0
5
10
Integer work mat
15
20
How to use the “Integer work mat”
• Each blue counter is worth +1
• Each red counter is worth -1 (in other words ‘the opposite of 1’)
• If the mathematical operation is addition, this means putting
something down onto the mat
• If the mathematical operation is subtraction, this means removing
something from the mat
First, let’s look at ‘addition’…
Start with three
positive counters
Add to this by putting
down onto the mat…
One negative counter
3 + −1
Start with three
positive counters
Add to this by putting
down onto the mat…
Two negative counters
3 + −2
Start with three
positive counters
Add to this by putting
down onto the mat…
Five negative counters
3 + −5
Start with three
negative counters
Add to this by putting
down onto the mat…
Two negative counters
−3 + −2
Start with three
negative counters
Add to this by putting
down onto the mat…
Two positive counters
−3 + 2
Start with three
negative counters
Add to this by putting
down onto the mat…
Five positive counters
−3 + 5
Key Questions about Addition:
1. Which direction do you move on the number line
when adding a positive integer?
2. Which direction do you move on the number line
when adding a negative integer?
Practice these addition situations:
1) 2 + 7 =
2) 2 + −7 =
3) −2 + 7 =
4) −2 + −7 =
5) −4 + 2 =
6) −4 + −2 =
7) −6 + −1 =
8) 5 + −11 =
Now, let’s look at ‘subtraction’…
What does it mean to ‘subtract’ something?
Subtract from this by
removing from the mat…
Start with three
positive counters
One positive counter
3−1
Subtract from this by
removing from the mat…
Start with three
positive counters
Five positive counters
3−5
Subtract from this by
removing from the mat…
Start with three
positive counters
Five negative counters
3 − −5
Subtract from this by
removing from the mat…
Start with three
positive counters
One negative counter
3 − −1
Subtract from this by
removing from the mat…
Start with three
negative counters
One negative counter
−3 − −1
Subtract from this by
removing from the mat…
Start with three
negative counters
One positive counter
−3 − 1
Key Questions about Subtraction:
1. Which direction do you move on the number line
when subtracting a positive integer?
2. Which direction do you move on the number line
when subtracting a negative integer?
Practice these subtraction situations:
1) 2 − 7 =
2) 2 − −7 =
3) −2 − 7 =
4) −2 − −7 =
5) 6 − 2 =
6) 6 − 10 =
7) −7 − −1 =
8) −4 − −11 =