MFM1P0 Foundations of Math
Unit 1: REVIEW
Day 2: Adding and Subtracting Integers
Learning Goal: I can add and subtract integers using a number line and
algebra tiles.
What is an integer?
An integer is a positive or negative whole number  draw a number line
Activity: I walk the Line
Tape a masking tape line down the center of the classroom as an integer line.
The first number is the starting point.
Adding faces to the right / Subtracting faces to the left.
Positive is walking forward. Negative is walking backwards.
Ex: -4 – (+3)
Start at -4. I am subtracting so I am going to face left. I subtract a
positive three so I walk forward.
Ex. 5 – (-2)
Start at 5. I am subtracting so I am going to face left. I subtract
negative two so I walk backwards.
Give everyone a chance to “walk the line.” Use a deck of cards to
determine the integers.
Adding and subtracting integers using Algebra tiles.
Using just the “ones” algebra tiles, demonstrate:
~ positive (red) vs negative (white – student’s need to flip tile over)
Adding Integers – use the overhead algebra tiles
a) Using the algebra tiles, show (+3) + (+5) = (+8)
b) Using the algebra tiles, show (-7) + (-2) = (-9)
c) Using the algebra tiles, demonstrate the “zero principle”.
 What can you add to a number, and still end up with the same number?
(Zero)
 How can you use algebra tiles to show zero? Using opposite integers (-2
& +2).
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MFM1P0 Foundations of Math
d) Using the algebra tiles, show (-8) + (+3) = (-5)
 using the zero principal - we match as many negative 1’s up with positive
1’s so that we can take them out of the pile since they add to zero
Subtracting Integers – use the overhead algebra tiles
a) Using algebra tiles, show (+4) - (-5) = (+9)
 using the zero principle – we can add as many opposite integers that
we want and it will not change the question so add a +1 tile and a -1
tile 5 times to get (-5) algebra tiles so we can take (-5) away form (+4)
b) Using algebra tiles, show (-3) – (+9) = (-12)
Homework:
Integer Concepts Worksheet
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MFM1P0 Foundations of Math
Name:
Integer Concepts
1.
1.
Use an integer to represent each amount.
a) 25º below zero
_____
b) walk up 3 steps
_____
c) 25º above zero
_____
d) a loss of 40 yards
_____
e) withdraw $50
_____
f) 7 over par
_____
g) a loss of 16 points
_____
h) you win $500
_____
i) $25 increase in pay
_____
j) you borrow $92
_____
Write the opposite of each integer.
a) +8 ______
b) -2 _______
c) -1 ______
d) +24 ______
e) When opposite integers are added together, what do they equal?
____________
2.
Use algebra tiles or a number line to help simplify the following.
a) (+3) + (-4) = _____
b) (-6) + (-1) = _____
c) (+12) + (-12) = _____
d) (-2) + (-5) = _____
e) (+4) + (-7) = _____
f) (-6) + (+8) = _____
g) (+10) + (-4) + (-3) = _____
h) (-2) + (-9) + (+6) = _____
i) (+3) - (-4) = _____
j) (-6) - (-1) = _____
k) (+12) - (-12) = _____
l) (-2) - (-5) = _____
m) (+4) - (-7) = _____
n) (-6) - (+8) = _____
o) (+10) - (-4) - (-3) = _____
p) (-2) - (-9) - (+6) = _____
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MFM1P0 Foundations of Math
Name: Answers
Integer Concepts
1.
2.
Use an integer to represent each amount.
a) 25º below zero
-25
b) walk up 3 steps
+3
c) 25º above zero
+25
d) a loss of 40 yards
-40
e) withdraw $50
-50
f) 7 over par
+7
g) a loss of 16 points
-16
h) you win $500
+500
i) $25 increase in pay
+25
j) you borrow $92
-92
Write the opposite of each integer.
a) +8 (-8)
b) -2 (+2)
c) -1 (+1)
d) +24 (-24)
e) When opposite integers are added together, what do they equal?
zero
3.
Use algebra tiles or a number line to help simplify the following.
a) (+3) + (-4) = -1
b) (-6) + (-1) = -7
c) (+12) + (-12) = 0
d) (-2) + (-5) = -7
e) (+4) + (-7) = -3
f) (-6) + (+8) = 2
g) (+10) + (-4) + (-3) = 3
h) (-2) + (-9) + (+6) = -5
i) (+3) - (-4) = 7
j) (-6) - (-1) = -5
k) (+12) - (-12) = 24
l) (-2) - (-5) = 3
m) (+4) - (-7) = 11
n) (-6) - (+8) = -14
o) (+10) - (-4) - (-3) = 17
p) (-2) - (-9) - (+6) = 1
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MFM1P0 Foundations of Math
Adding
Subtracting
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MFM1P0 Foundations of Math
Positive number
walk forward
Negative number walk
backward
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