Course 2, Lesson 3-1

Lesson 1: Integers and Absolute Value

Chapter 3

Course 2, Lesson 3-1

WHAT happens when you add,

subtract, multiply, and divide integers?

• To identify and graph integers
• To find absolute value

Course 2, Lesson 3-1

• integer
• negative integer
• positive integer
• graph
• absolute value

Course 2, Lesson 3-1

1

Step-by-Step Example

Write an integer for the situation.

1.

an average temperature of 5 degrees below normal

Because it represents below normal, the integer is –5.

Answer

Need Another Example?

a loss of 12 yards

−12

1

Step-by-Step Example

2.

Write an integer for the situation.

an average rainfall of 5 inches above normal

Because it represents above normal, the integer is +5 or 5.

Answer

Need Another Example?

a snowfall of 4 inches above normal

+4

1

Step-by-Step Example

3.

Graph the set of integers {4, –6, 0} on a number line.

Draw a number line. Then draw a

dot at the location of each integer

Answer

Need Another Example?

Graph the set of integers {–1, 3, –2} on a number line.

Course 2, Lesson 3-1

Absolute Value

Words The absolute value of a number is the distance between

the number and zero on a number line.

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Examples

1

2

3

Step-by-Step Example

4.

Evaluate the expression.

| –4 |

The graph of –4 is 4 units from 0.

4 Units

So, | –4 | = 4.

Answer

Need Another Example?

Evaluate | –5 |.

5

1

| –5 | – | 2 |

2

Step-by-Step Example

5.

Evaluate the expression.

| –5 | – | 2 | = 5 – 2

| –5 | = 5, | 2 | = 2

So, | –5 | – | 2 | = 3.

Answer

Need Another Example?

Evaluate | –4 | – | –3 |.

1

1

2

3

Step-by-Step Example

6.

Nick climbs 30 feet up a rock wall and then climbs

22 feet down to a landing area. The number of feet Nick climbs can be represented using the expression | 30 | + | –22 |. How many feet does Nick climb?

| 30 | + | –22 | = 30 + | –22 |

The absolute value of 30 is 30.

The absolute value of –22 is 22. Simplify.

= 30 + 22 or 52

So, Nick climbs 52 feet.

Answer

Need Another Example?

Megan’s dog gained weight and then lost weight. The number of pounds her dog gained and then lost is represented by the expression | 6 | + | –3 |. How many pounds did Megan’s dog gain and lose?

9 pounds

How did what you learned

today help you answer the

WHAT happens when you add,

subtract, multiply, and divide integers?

Course 2, Lesson 3-1

How did what you learned

today help you answer the

WHAT happens when you add,

subtract, multiply, and divide integers?

Course 2, Lesson 3-1

Sample answers:

• Integers can be used to represent real-world situations.
• You can evaluate absolute value expressions involving integers.

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Describe a�real-world situation�that uses integers.

Course 2, Lesson 3-1

Ratios and Proportional Relationships