MFM1P1
Lesson 1_4
Addition of Integers
One way to add integers is to think of MONEY. -2 means "You owe $2"
+2 means "You have $2"
NOTE: 2 means +2 (The positive sign is understood)
When we ADD integers, this game still works.
 2  6 means "You owe $2" AND "You have $6"
Once you complete the transaction…you still have $4.
Therefore,  2  6  4
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Example 1: Using the MONEY game (above), explain what each of the following mean?
(a)
(b)
(c)
(d)
(e)
 3 means "You owe $3 "
means "You have $8"
8
means "You owe $1" and "You have $9" = "You have $8"
 1 9
7    4
means "You have $7" and "You owe $4" = "You have $3"
6    7
means "You have $6" and "You owe $7" = "You owe $1"
Therefore, in Ex 1(e) we can say that 6    7  1
Example 2: Add.
(a) 15  11
(b)  7  5
(c)  7    5
(d)  4  13
(e)  23  6
(f) 85  81
(g)  4  19
(h) 3  37
(i)  2    15
(j) 6    46
(k)  123    9
(l)   8    7
Subtraction of Integers
To subtract integers "ADD THE OPPOSITE"
We say that -2 is the opposite of +2
+7 is the opposite of -7
Consider the expression  2    9
=  2    9
= 11
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Example 1: Subtract.
(a)   4    1
(b)   7    8
(c) 9  7
(d) 4  9
(e)   11    6
(f)   9    11
(g)   4    11
(h) 28  37
Example 2: Simplify.
(a)   5    2    6
(b)   3    9    1
(c) 8    7  2
(d)  5    2  9
Seatwork: Worksheet "Subtracting Integers"
Homework: Worksheets: "Subtracting Integers = Adding The Opposite"
"What do Vampires Do On Halloween?"
"Find A Match"
MFM1P1
Lesson 1_4
Adding Integers
Put all answers in the space provided.
(a)  8  2
(b)  3    1
(c)  5  9
(d)  9    9
(e) 3  4
(f) 6    7
(g) 8    5
(h)  2  7
(i)  9    6
(j) 3    9
(k) 61    12
(l)  165    92
(m)  85  48
(n)  105  113
(o)  285  198
(p)  95  93
MFM1P1
Lesson 1_4
Subtracting Integers
Put all answers in the space provided.
1. Subtract the following.
(a)   9    4
(b)   5    6
(c) 7    3
(d) 0    2
(e)   9    12
(f)   14    7
(g) 23    6
(h)  21  37
2. Simplify.
(a)   8    4    2
(j)   2    3    5
(k) 7    2  5
(l) 7    6    8
(m)   4    1    3
(n)   7    5    6
Subtracting Integers = Adding The Opposite
1. Subtract.
(a) 11  3
(b) 9  2
(c) 15    2
(d) 7    7
(e)  5  3
(f)  12    7
(g) 0  3
(h) 8    2
(i) 0    2
(j)  15    9
(k)  3    11
(l) 21    7
(m)  8    3
(n) 12    3
(o) 70  5
(p)  17  22
(q) 3    3
(r)  7  10
(s) 27    30
(t) 45    10
(u)  32  3
(v) 50  17
(w)  12  2
(x) 8    1
(y)  5  3
(z)  7  3
2. Simplify.
(a) 4  7  3
(b)  4  5    2
(c)  7    5  5
(d) 5    3  2
(e) 4  9    1
(f)  3  4  1
(g)  2  4    3
(h) 4  7  9
(i)  3  5  2