1. Subtracting Integers with Tiles
Lesson 2.4
Subtracting Integers with Tiles

2. When we added integers using tiles, we combined the tiles together.
When we subtract, we remove tiles from a group.

3. Remember that equal numbers of red and yellow model 0.
Adding a zero pair to a set of tiles does not change its value.

4. To use tiles to subtract integers, model the integer first, then take away the number of tiles indicated by the second integer.

5. (+5) – (+9)
Model +5
There are not enough tiles to take away 9.
We need 4 more tiles...

6. This is a subtraction equation...
We can add zero pairs without changing the value of the equation. Add 4 yellow tiles...then add 4 red tiles.
We can now take away 9 yellow tiles.
Only 4 red tiles remain. (+5) + (+9) = -4
This is a subtraction equation...

7. (-2) – (-6) = Model -2. There are not enough tiles to take away -6
(-2) – (-6) = Model -2. There are not enough tiles to take away -6. Add enough zero pairs to be able to take away -6. Now, we can take 6 red tiles away. Then we write: (-2) – (-6) = +4

8. (-6) – (+2) Model -6
In this example, there are no yellow tiles to take away. So, add two zero pairs.
Take away the two yellow tiles. There are 8 red tiles left...
Then you have (-6) – (+2) = -8

9. (+2) + (-6) Model +2
There are no red tiles to take away at first. So, add zero pairs. Then take away 6 red tiles.
Since 8 yellow tiles remain, the answer is +8.

10. Use tiles to subtract these...
(+7) – (-4)
(-3) – (-9)
(-5) – (+2)
(+6) – (+8)

11. Homework
Workbook 2.4
Textbook Page #2,5,7 and Reflect