# Add and Subtract Integers Investigation

Name: _____________________________ Date:_____________
Block: __________
PURPOSE: To practice adding and subtracting integers with number lines
and algebra tiles (charge method).
SOL: 7.3
NUMBER LINES
Examples:
Use the below number lines to model the given ADDITION problems:
1.
4 + 3 = _____
2.
7 + (-3) = _____
3.
-6 + (-3) = _____
4.
-10 + 2 = _____
5.
-2 + (-6)= _____
6.
-4 + 7 = _____
7.
-7 + (-1) = _____
8.
-6 + 8 = _____
9.
10 + (-8) = _____
10. 1 + (-5)= _____
11. -3 + 0 = _____
12. -9 + (-1) = _____
13.
-3 + 9 = ______
PART TWO – Algebra Tiles/Charge Method
Example:
7 + 12 = 19
COMBINE
Key:
= Positive
= Negative
Directions:
Draw tiles onto below mats in order to model given problems (you may use “+” signs for
positives and “-” signs for negatives:
1.
Represent 2 + 5 in the mat below.
2 + 5 = ______
2.
Represent 8 + 3 in the mat below.
8 + 3= ______
3.
Represent 9 + 0 in the mat below.
9 + 0 = ______
4.
Represent 4 + 6 in the mat below.
4 + 6= ______
6. In the space below, write a rule for adding two positive numbers.
6. Represent -4 + 9 in the mat to the right.
Circle the zero pair(s).
How many zero pairs are in the problem ? _____
What is the solution to -4 + 9 ? _____
7. Represent 2 + (-3) in the mat to the right.
Circle the zero pair(s).
How many zero pairs are in the problem ? _____
What is the solution to 2 + (-3) ? _____
8. Represent -2 + 8 in the mat to the right.
Circle the zero pair(s).
How many zero pairs are in the problem ? _____
What is the solution to -2 + 8 ? _____
9. Represent 3 + (-5) in the mat to the right.
Circle the zero pair(s).
How many zero pairs are in the problem ? _____
What is the solution to 3 + (-5) ? _____
11. How can you predict the sign of the sum (answer) before you actually “do the math”?
12. Write a rule that works for adding integers with different signs.
NAME:__________________________
DATE: ______/_______/_______
Represent the following problems on the given number lines:
1. -2 + 6 = ………..
2. -4 + -2 = ……….
3. -5 + 3 = ……….
4. 2 + 5 = ……….
5. 9 + (-4) = ……….
6. -3 + (-4) = ……….
7. -8 + (-1) = ……….
8. 5 + (-4) = ……….
9. 3 + 6 = ……….
10. -1 + (-6) = ……….
Directions: Draw tiles onto below mats in order to model the given problems :
1.
4 + (-3) = _____
2.
-8 + (-4) = _____
3.
7 + 5 = _____
4.
-12 + (3) = _____
5.
9 + (-2) = _____
6.
-7 + (-6) = _____
Key:
+
= Positive
-
= Negative
Name:_______________________
Date: _______________________
Subtraction Modeling Lab
PART ONE -- NUMBER LINES
Start
Examples : 5 – 8 = -3
End
Start
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) = _____
End
PART TW0 – ALGEBRA TILES / Charge Method
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? _______
Circle what
needs to be
taken away.
What’s left?
Subtraction with “Zero Pairs”:
Example:
8 -10 = -2
Step One:
Step Two:
Step Three:
NOW,
take the
10 away!
Do we have
10 positives
to take
away??
6.
. . . So, we have
pairs in order to
make 10
positives!
-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? _________
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) ?
14. Write a rule that works for subtracting integers.
NAME:__________________________
“subtraction INTEGER MODELING”
DATE: ______/_______/_______
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) = ……….
Algebra Tiles/ Charge Method Subtraction
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