Warm Up

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Warm Up
Problem of the Day
Lesson Presentation
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Warm Up Graph each number on a number line. 1.
5 2. 7 3. 4 4. 0
Add. 5. 22 19 6. 17 18
35
41
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Problem of the Day Start at (0, 0). Walk 3
blocks west and 2 blocks north. Then walk 4
blocks south and 1 block east. What are your
coordinates?
(2, 2)
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Learn to add integers.
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Insert Lesson Title Here
Vocabulary
integer opposite absolute value
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Integers are sets of whole numbers, including 0,
and their opposites. The sum of two opposite
integers is zero.
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Additional Example 1 Using a Number Line to Add
Integers
Use a number line to find the sum. (6) 2
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You finish at 4, so (6) 2 4.
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Try This Example 1
Use a number line to find the sum. (3) 7
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You finish at 4, so (3) 7 4.
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Another way to add integers is to use absolute
value. The absolute value of a number is its
distance from 0. The absolute value of 4,
written as 4, is 4 and the absolute value of
5 is 5.
Adding integers Adding integers
If the signs are the same. . . If the signs are different. . .
find the sum of the absolute values. Use the same sign as the integers. find the difference of the absolute values. Use the sign of the integer with the larger absolute value.
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Additional Example 2A 2B Using Absolute Value
to Add Integers
Add.
A. 1 (2)
1 (2)
Think Find the difference of 2 and 1.
2 gt 1 use the sign of 2.
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B. (8) 5
Think Find the difference of 8 and 5.
(8) 5
8 gt 5 use the sign of 8.
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Additional Example 2C Using Absolute Value to
Add Integers
Add.
C. (2) (4)
(2) (4)
Think Find the sum of 2 and 4.
Same sign use the sign of the integers.
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Try This Example 2A 2B
Add.
A. 3 (6)
3 (6)
Think Find the difference of 6 and 3.
6 gt 3 use the sign of 6.
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B. (4) 1
Think Find the difference of 4 and 1.
(4) 1
4 gt 1 use the sign of 4.
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Try This Example 2C
Add.
C. (6) (7)
(6) (7)
Think Find the sum of 6 and 7.
Same sign use the sign of the integers.
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Additional Example 3 Evaluating Expressions with
Integers
Evaluate c 4 for c 8.
c 4
Replace c with 8.
(8) 4
Think Find the difference of 8 and 4.
8 gt 4 use the sign of 8.
8 4 4
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Try This Example 3
Evaluate d 7 for d 3.
d 7
Replace d with 3.
(3) 7
Think Find the difference of 7 and 3.
7 gt 3 use the sign of 7.
3 7 4
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Additional Example 4 Application
Katrina opened a new bank account. Find her
account balance after the first four transactions
listed below.
Deposits 200, 20 Withdrawals 166, 38
Use a positive sign for deposits and a negative
sign for withdrawals.
200 20 (166) (38)
Group integers with same signs.
(200 20) (166 38)
Add integers within each group.
220 (204)
220 gt 204 use the sign of 220.
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Katrinas account balance after the first four
transactions is 16.
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Try This Example 4
Michael opened a new bank account. Find his
account balance after the first four transactions
listed below.
Deposits 175, 95 Withdrawals 133, 65
Use a positive sign for deposits and a negative
sign for withdrawals.
175 95 (133) (65)
Group integers with same signs.
(175 95) (133 65)
Add integers within each group.
270 (198)
270 gt 198 use the sign of 270.
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Michaels account balance after the first four
transactions is 72.
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Insert Lesson Title Here
Lesson Quiz Part 1
Add. 1. 7 ( 7) 2. 15 (9) (2)
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Evaluate each expression for the given value of
the variable. 3. 13 r for r 15 4. 2 b
(9) for b 6
2
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Insert Lesson Title Here
Lesson Quiz Part 2
5. On Monday, a local dog shelter had six dogs.
By Friday they had found homes for three, but
took in two more. Then how many dogs were in the
shelter?
5 dogs