Subtraction Modeling Lab

Name:_______________________Date: _______________________

PART ONE -- NUMBER LINES

Examples : 5 – 8 = -3

3 – (-3) = 6

Use the below number lines to model the given subtraction problems:

1. 4 – 3 = _____

2. 7 – 9 = _____

3. -6 – 3 = _____

4. -4 – 2 = _____

5. -2 – (-6)= _____

6. -5 – (-3) = _____

7. 8 – 2 = _____

8. 7 – (-2) = _____

9. 4 – 7 = _____

10. 2 – (-5) = _____

PURPOSE: To practice subtracting integers with both number lines and algebra tiles.

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PART TW0 – ALGEBRA TILES

Example: 8 – 6 = 2

1. 9 – 2

Put 9 positive tiles on the mat. Take 2 positive tiles away.

How many do you have left? _______

2. 7 – 5

Put 7 positive tiles on your mat. Take 5 positive tiles away.

How many do you have left? _______

3. -9 – (-3)

Put 9 negative tiles on your mat.Take 3 negative tiles away.

How many do you have left? _______

4. -3 – (-2)

Put 3 negative tiles on your mat.Take 2 negative tiles away.

How many do you have left? _______

Start with 8. Circle what needs to be

taken away. What’s left?

Answer:

Subtraction with “Zero Pairs”:

Example: 8 -10 = -2

6. -1 – 2 Put 1 negative tile on your mat.

Do you have 2 positive tiles to take away? ______

How can you put 2 positive tiles on your mat without changing the overall value (or “charge”) of the mat?

How many zero pairs did you add?_______ Take away 2 positive tiles.

What do you have left? _______ (This is the answer!)

7. -4 – 3 Put 4 negative tiles on your mat. Add zero pairs in order to take away 3 positive tiles.

How many zero pairs did you add? ________

What do you have left? ________

8. -7 – 5 Put 7 negative tiles on your mat. Add zero pairs in order to take away 5 positive tiles.

How many zero pairs did you add? _________

What do you have left? _________

Answer:Do we have 10 positives

to take away??

Step Two:Step One: Step Three:

. . . So, we have to add 2 zero

pairs in order to make 10

positives!

NOW, take the 10 away!

9. 1 – (- 2) Put 1 positive tile on your mat. Add zero pairs in order to take away 2 negative tiles.

How many zero pairs did you add?_______

What do you have left? _______

10. 4 – (- 3) Put 4 positive tiles on your mat. Add zero pairs in order to take away 3 negative tiles.

How many zero pairs did you add? ________

What do you have left? ________

11. 7 – (-5) Put 7 positive tiles on your mat. Add zero pairs in order to take away 5 negative tiles.

How many zero pairs did you add? _________

What do you have left? _________

12. Why are zero pairs important?

13. Do you need zero pairs to solve the following: -2 – (-8) ?Use a visual to support your answer.

14. Write a rule that works for subtracting integers.

Represent the following problems on the given number lines:

1. 6 – 2 = ………..

2. 3 – 7 = ……….

3. -6 – 3 = ……….

4. -1 – 5 = ……….

5. 2 – (-4) = ……….

6. -2 – (-5) = ……….

7. -8 – 1 = ……….

8. 5 – (-2) = ……….

9. 3 – 6 = ……….

10. -1 – (-6) = ……….

Math-7 PRACTICE DATE: ______/_______/_______NAME:__________________________

“subtraction MODELING”

Directions: Draw tiles onto below mats in order to model the given problems . Remember, if you don’t have the necessary tiles, you need to ADD zero pairs!

1. 4 – 2 = _____

2. -8 – (-4) = _____

3. -8 – 5 = _____

4. 10 – (-3) = _____

5. -9 – (-2) = _____

6. -7 – 9 = _____

Key: + = Positive - = Negative

Algebra Tiles Subtraction