# Percents Decimals and 7 8 Percents Decimals and

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Percents, Decimals, and 7 -8 Percents, Decimals, and Fractions 7 -8 Fractions Warm Up Problem of the Day Lesson Presentation Course 11

7 -8 Percents, Decimals, and Fractions Repeating Decimals as Fractions: 1. Note how many digits are being repeated. 2. Place that amount of 9’s in the denominator. 3. Write the repeated digit(s) as the numerator. Examples: Course 1

7 -8 Percents, Decimals, and Fractions How Did That Work? • Let N = • Then 1000 N = 123123123… • We can subtract N from 1000 N: • 999 N = 123, so Course 1

7 -8 Percents, Decimals, and Fractions Place Value Course 1

7 -8 Percents, Decimals, and Fractions • To change a decimal into a percent, multiply the decimal by 100. • Remember that percent is based on 100. A whole is 100%. • Examples: – 0. 7; 0. 7 x 100 = 70% (the decimal moved 2 spaces to the right) – 0. 07; 0. 07 x 100 = 7% Course 1

7 -8 Percents, Decimals, and Fractions Additional Example 1 A: Writing Decimals as Percents Write the decimal as a percent. Method 1: Use place value. 0. 7 7 0. 7 = __ 10 Write the decimal as a fraction. 7 • 10 = ___ 70 Write an equivalent fraction with _______ 10 • 10 100 as the denominator. 70 = 70% Write the numerator with a percent ___ 100 symbol. Course 1

7 -8 Percents, Decimals, and Fractions Additional Example 1 B: Writing Decimals as Percents Write the decimal as a percent. Method 1: Use place value. 0. 16 16 Write the decimal as a fraction. 0. 16 = __ 100 16 = 16% Write the numerator with a percent ___ 100 symbol. Course 1

7 -8 Percents, Decimals, and Fractions Additional Example 1 C: Writing Decimals as Percents Write the decimal as a percent. Method 2: Multiply by 100. 0. 4118 • 100 41. 18% Course 1 Multiply by 100. Add the percent symbol.

7 -8 Percents, Decimals, and Fractions Additional Example 1 D: Writing Decimals as Percents Write the decimal as a percent. Method 2: Multiply by 100. 0. 067 • 100 6. 7% Course 1 Multiply by 100. Add the percent symbol.

7 -8 Percents, Decimals, and Fractions Check It Out: Example 1 A Write the decimal as a percent. Method 1: Use place value. 0. 9 9 0. 9 = __ 10 Write the decimal as a fraction. 9 • 10 = ___ 90 Write an equivalent fraction with _______ 10 • 10 100 as the denominator. 90 = 90% Write the numerator with a percent ___ 100 symbol. Course 1

7 -8 Percents, Decimals, and Fractions Check It Out: Example 1 B Write the decimal as a percent. Method 1: Use place value. 0. 31 = 31 Write the decimal as a fraction. 100 31 = 31% Write the numerator with a percent ___ 100 symbol. Course 1

7 -8 Percents, Decimals, and Fractions Check It Out: Example 1 C Write the decimal as a percent. Method 2: Multiply by 100. 0. 1225 • 100 12. 25% Course 1 Multiply by 100. Add the percent symbol.

7 -8 Percents, Decimals, and Fractions Check It Out: Example 1 D Write the decimal as a percent. Method 2: Multiply by 100. 0. 023 • 100 2. 3% Course 1 Multiply by 100. Add the percent symbol.

7 -8 Percents, Decimals, and Fractions Helpful Hint 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. Course 1

7 -8 Percents, Decimals, and Fractions Additional Example 2 A: Writing Fractions as Percents Write the fraction as a percent. Method 1: Write an equivalent fraction with a denominator of 100. 9 __ 25 9 • 4 = ___ 36 Write an equivalent fraction with ______ 25 • 4 100 as the denominator. 36 = 36% Write the numerator with a percent ___ 100 symbol. Course 1

7 -8 Percents, Decimals, and Fractions Additional Example 2 B: Writing Fractions as Percents Method 2: Use division to write the fraction as a decimal. 3 __ 20 0. 15 Divide the numerator by the 20 3. 00 denominator. – 20 100 – 100 0 Multiply by 100 by moving the 0. 15 = 15% decimal point right two places. Add the percent symbol. Course 1

7 -8 Percents, Decimals, and Fractions Check It Out: Example 2 A Write the fraction as a percent. Method 1: Write an equivalent fraction with a denominator of 100. 7 __ 50 7 • 2 = ___ 14 Write an equivalent fraction with ______ 50 • 2 100 as the denominator. 14 = 14% Write the numerator with a percent ___ 100 symbol. Course 1

7 -8 Percents, Decimals, and Fractions Check It Out: Example 2 B Method 2: Use division to write the fraction as a decimal. 8 __ 50 0. 16 50 8. 00 0. 16 = 16% Course 1 Divide the numerator by the denominator. Multiply by 100 by moving the decimal point right by two places. Add the percent symbol.

7 -8 Percents, Decimals, and Fractions Additional Example 3: Application 7 of people with home offices One year, __ 25 were self-employed. What percent of people with home offices were self employed? 7 __ 25 7 • 4 28 Write an equivalent fraction with a ______ = ___ 25 • 4 100 denominator of 100. 28 ___ = 28% 100 28% of people with home offices were self-employed. Course 1

7 -8 Percents, Decimals, and Fractions Check It Out: Example 3 3 of people who bought new cars One year, __ 50 bought cars that were yellow. What percent of people that bought new cars bought yellow cars? 3 __ 50 3 • 2 6 ______ Write an equivalent fraction with a = ___ 50 • 2 100 denominator of 100. 6 ___ = 6% 100 6% of people with new cars bought yellow cars. Course 1

7 -8 Percents, Decimals, and Fractions Course 1

7 -8 Percents, Decimals, and Fractions Lesson Quiz Write each decimal as a percent. 1. 0. 26 26% 2. 0. 419 41. 9% Write each fraction as a percent. 9 1 __ __ 56. 25% 20% 3. 5 4. 16 1 5. About __ of all the students at a local high 16 school own their own car. What percent is this? 6. 25% Course 1