8-8 Percents, Decimals, and Fractions

Course 1

Warm Up

Lesson Presentation

Problem of the Day

Warm UpWrite each percent as a fraction in simplest form.

1. 37% 2. 78%

Write each percent as a decimal.

3. 59% 4. 7%0.59 0.07

Course 1

8-8 Percents, Decimals, and Fractions

37100

___ 39 50

___

Problem of the Day

Jennifer gave Karen 50% of her comic books. Karen gave Jack 50% of the books she got from Jennifer. Jack gave Lucas 50% of the books he got from Karen. Lucas got 4 comic books. What percent of Jennifer’s comic books does Lucas have?

12.5%

Course 1

8-8 Percents, Decimals, and Fractions

Learn to write decimals and fractions as percents.

Course 1

8-8 Percents, Decimals, and Fractions

Course 1

8-8 Percents, Decimals, and Fractions

Additional Example 1A: Writing Decimals as Percents

Write each decimal as a percent.

Method 1: Use place value.

A. 0.7

Write the decimal as a fraction.

Write an equivalent fraction with 100 as the denominator.

0.7 = 710

__

7 • 1010 • 10

_______ = 70100

___

70100

___ = 70% Write the numerator with a percent symbol.

Course 1

8-8 Percents, Decimals, and Fractions

Additional Example 1B: Writing Decimals as Percents

Write each decimal as a percent.

Method 1: Use place value.

B. 0.16

Write the decimal as a fraction.0.16 = 16 100

__

16100

___ = 16% Write the numerator with a percent symbol.

Course 1

8-8 Percents, Decimals, and Fractions

Additional Example 1C: Writing Decimals as Percents

Write each decimal as a percent.

Method 2: Multiply by 100.

C. 0.4118

Multiply by 100.0.4118 • 100

41.18% Add the percent symbol.

Course 1

8-8 Percents, Decimals, and Fractions

Additional Example 1D: Writing Decimals as Percents

Write each decimal as a percent.

Method 2: Multiply by 100.

D. 0.067

Multiply by 100.0.067 • 100

6.7% Add the percent symbol.

Course 1

8-8 Percents, Decimals, and Fractions

Try This: Example 1A

Write each decimal as a percent.

Method 1: Use place value.

A. 0.9

Write the decimal as a fraction.

Write an equivalent fraction with 100 as the denominator.

0.9 = 910

__

9 • 1010 • 10

_______ = 90100

___

90100

___ = 90% Write the numerator with a percent symbol.

Course 1

8-8 Percents, Decimals, and Fractions

Try This: Example 1B

Write each decimal as a percent.

Method 1: Use place value.

B. 0.31

Write the decimal as a fraction.0.31 =

31100

___ = 31% Write the numerator with a percent symbol.

31100

Course 1

8-8 Percents, Decimals, and Fractions

Try This: Example 1C

Write each decimal as a percent.

Method 2: Multiply by 100.

C. 0.1225

Multiply by 100.0.1225 • 100

12.25% Add the percent symbol.

Course 1

8-8 Percents, Decimals, and Fractions

Try This: Example 1D

Write each decimal as a percent.

Method 2: Multiply by 100.

D. 0.023

Multiply by 100.0.023 • 100

2.3% Add the percent symbol.

Course 1

8-8 Percents, Decimals, and Fractions

When the denominator is a factor of 100, it is often easier to use method 1. When the denominator is not a factor of 100, it is usually easier to use method 2.

Helpful Hint

Course 1

8-8 Percents, Decimals, and Fractions

Additional Example 2A: Writing Fractions as Percents

Write an equivalent fraction with 100 as the denominator.

9 • 425 • 4

______ = 36100

___

36100

___ = 36% Write the numerator with a percent symbol.

925

__

Write each fraction as a percent.

Method 1: Write an equivalent fraction with a denominator of 100.

A.

Course 1

8-8 Percents, Decimals, and Fractions

Additional Example 2B: Writing Fractions as Percents

Divide the numerator by the denominator.

0.15 = 15% Multiply by 100 by moving the decimal point right two places. Add the percent symbol.

320

__

100

20 3.000.15

–20

–1000

Method 2: Use division to write the fraction as a decimal.

B.

Course 1

8-8 Percents, Decimals, and Fractions

Try This: Example 2A

Write each fraction as a percent.

Method 1: Write an equivalent fraction with a denominator of 100.

A.

Write an equivalent fraction with 100 as the denominator.

7 • 250 • 2

______ = 14100

___

14100

___ = 14% Write the numerator with a percent symbol.

750

__

Course 1

8-8 Percents, Decimals, and Fractions

Try This: Example 2B

Divide the numerator by the denominator.

0.16 = 16% Multiply by 100 by moving the decimal point right by two places. Add the percent symbol.

850

__

50 8.000.16

Method 2: Use division to write the fraction as a decimal.

B.

Course 1

8-8 Percents, Decimals, and Fractions

Additional Example 3: Application

One year, of people with home offices

were self-employed. What percent of people with home offices were self employed?

Write an equivalent fraction with a denominator of 100.

7 • 425 • 4

______ = 28100

___

28100

___ = 28%

725

__

725

__

28% of people with home offices were self-employed.

Course 1

8-8 Percents, Decimals, and Fractions

Try This: Example 3

One year, of people who bought new cars

bought cars that were yellow. What percent of people that bought new cars bought yellow cars?

Write an equivalent fraction with a denominator of 100.

3 • 250 • 2

______ = 6100

___

6100

___ = 6%

350

__

350

__

6% of people with new cars bought yellow cars.

Course 1

8-8 Percents, Decimals, and Fractions

Lesson Quiz

Write each decimal as a percent.

1. 0.26 2. 0.419

Write each fraction as a percent.

3. 4.

5. About of all the students at a local high

school own their own car. What percent is this?

41.9%26%

Insert Lesson Title Here

20% 56.25%

Course 1

8-8 Percents, Decimals, and Fractions

1 5

__ 916

__

116

__

6.25%