# Subtraction Modeling Lab PART ONE -- NUMBER LINES

## Presentation on theme: "Subtraction Modeling Lab PART ONE -- NUMBER LINES"— Presentation transcript:

Subtraction Modeling Lab PART ONE -- NUMBER LINES
Name:_______________________ Date: _______________________ Subtraction Modeling Lab PURPOSE: To practice subtracting integers with both number lines and algebra tiles. PART ONE -- NUMBER LINES Examples : 5 – 8 = -3 3 – (-3) = 6 Use the below number lines to model the given subtraction problems: 4 – 3 = _____ 7 – 9 = _____ -6 – 3 = _____ -4 – 2 = _____ -2 – (-6)= _____ -5 – (-3) = _____ 8 – 2 = _____ 7 – (-2) = _____ 4 – 7 = _____ 2 – (-5) = _____ End Start End Start

Start with 8. Circle what needs to be taken away. What’s left?
PART TW0 – ALGEBRA TILES Example: 8 – 6 = 2 9 – 2 Put 9 positive tiles on the mat. Take 2 positive tiles away. How many do you have left? _______ 7 – 5 Put 7 positive tiles on your mat. Take 5 positive tiles away. -9 – (-3) Put 9 negative tiles on your mat. Take 3 negative tiles away. – (-2) Put 3 negative tiles on your mat. Take 2 negative tiles away. Start with 8. Circle what needs to be taken away. What’s left? Answer:

Subtraction with “Zero Pairs”:
Example: = -2 – 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!) – 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? ________ – 5 Put 7 negative tiles on your mat. 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!

– (- 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? _______ – (- 3) Put 4 positive tiles on your mat. 3 negative tiles. How many zero pairs did you add? ________ What do you have left? ________ – (-5) Put 7 positive tiles on your mat. 5 negative tiles. How many zero pairs did you add? _________ What do you have left? _________ 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.

Math-7 PRACTICE “subtraction MODELING”
DATE: ______/_______/_______ NAME:__________________________ “subtraction MODELING” Represent the following problems on the given number lines: – 2 = ……….. – 7 = ………. – 3 = ………. – 5 = ………. – (-4) = ………. – (-5) = ………. – 1 = ………. 5 – (-2) = ………. 3 – 6 = ………. -1 – (-6) = ……….

Algebra Tiles Subtraction
Key: + = Positive - = Negative 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! – 2 = _____ – (-4) = _____ – 5 = _____ – (-3) = _____ – (-2) = _____ – 9 = _____