Warm Up

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Warm Up
Problem of the Day
Lesson Presentation
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Warm Up Add or subtract. 1. 16 25 2. 84
12 3. Graph the even numbers from 1 to 10 on a
number line.
41
72
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Problem of the Day Carlo uses a double-pan
balance and three different weights to weigh bird
seed. If his weights are 1 lb, 2 lb, and 5 lb,
what whole pound amounts is he able to weigh?
1, 2, 3, 5, 6, 7, and 8 lb
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Learn to identify and graph integers, and find
opposites.
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Vocabulary
positive number negative number opposites integer
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Positive numbers are greater than 0. They may be
written with a positive sign (), but they are
usually written without it.
Negative numbers are less than 0. They are always
written with a negative sign ().
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Additional Example 1 Identifying Positive and
Negative Numbers in the Real World Name a
positive or negative number to represent each
situation. A. a jet climbing to an altitude of
20,000 feet B. taking 15 out of the bank
Positive numbers can represent climbing or rising.
20,000
Negative numbers can represent taking out or
withdrawing.
15
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Additional Example 1 Identifying Positive and
Negative Numbers in the Real World Name a
positive or negative number to represent each
situation. C. 7 degrees below zero
Negative numbers can represent values below or
less than a certain value.
7
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Check It Out Example 1 Name a positive or
negative number to represent each situation. A.
300 feet below sea level B. a hiker hiking to
an altitude of 4,000 feet
Negative numbers can represent values below or
less than a certain value.
300
Positive numbers can represent climbing or rising.
4,000
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Check It Out Example 1 Name a positive or
negative number to represent each situation. C.
spending 34
Negative numbers can represent losses or
decreases.
34
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You can graph positive and negative numbers on a
number line.
On a number line, opposites are the same distance
from 0 but on different sides of 0.
Integers are the set of all whole numbers and
their opposites.
Opposites
Positive Integers
Negative Integers
0 is neither negative nor positive.
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Additional Example 2 Graphing Integers Graph
each integer and its opposite on a number
line. A. 2
2 is the same distance from 0 as 2.
B. 5
5 is the same distance from 0 as 5.
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Additional Example 2 Graphing Integers Graph
each integer and its opposite on a number
line. C. 1
1 is the same distance from 0 as 1.
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Check It Out Example 2 Graph each integer and
its opposite on a number line. A. 3
3 is the same distance from 0 as 3.
B. 4
4 is the same distance from 0 as 4.
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Check It Out Example 2 Graph each integer and
its opposite on a number line. C. 0
Zero is its own opposite.
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Additional Example 3 Writing Integer Expressions
to Represent Situations Mark enters his office
building on the ground floor. Using the elevator,
he goes up 6 floors to place a call, then down 4
floors for lunch, and then up 8 floors for a
meeting. Write an expression to represent this
situation.
You can use a number line to model Marks
movements on the elevator.
Mark starts on the ground floor, 0.
0
Mark goes up 6 floors.
6
Mark goes down 4 floors.
-4
Mark goes up 8 floors.
8
6 4 8
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Check It Out Example 3 Maryl enters her office
building on the ground floor. Using the elevator,
she goes up 5 floors to her desk, then down 4
floors for lunch, and then up 6 floors for the
restroom. Write an expression to represent this
situation.
You can use a number line to model Maryls
movements on the elevator.
Maryl starts on the ground floor, 0.
0
Maryl goes up 5 floors.
6
Maryl goes down 4 floors.
-4
Maryl goes up 6 floors.
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5 4 6
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Lesson Quiz
Name a positive or negative number to represent
each situation. 1. saving 15 2. 12 feet below
sea level 3. What is the opposite of 6? 5. When
the Swanton Bulldogs football team passed the
football, they gained 25 yards. Write an integer
to represent this situation.
15
12
6
25