1. Preparation for NS1.4 Calculate given percentages of quantities and solve problems involving discounts at sales, interest earned, and tips.
California
Standards

2. Vocabulary:
Fraction to Decimal to Percent

3. A group of students plan to collect 2,000 cans of food for a food bank
A group of students plan to collect 2,000 cans of food for a food bank. After 10 days, they have 800 cans of food.

4. The model shows that 800 out of 2,000 can be written as , ,
200
400
600
800
1,000
1,200
1,400
1,600
1,800
2,000 1 5 2 5 3 5 4 5 5
0.2
0.4
0.6
0.8
1.0
20%
40%
60%
80%
100%
800
2000 2 5
The model shows that 800 out of 2,000 can be written as , ,
0.4, or 40%. The students have reached 40% of their goal.

5. Teacher Example 1: Writing Decimals as Percents
Write 0.7 as a percent.
Method 1: Use pencil and paper. 7 10 70
100
Write the decimal as a fraction with a denominator of 100.
0.7 = =
Write the numerator with a percent sign.
= 70%
Method 2: Use mental math.
Move the decimal point two places to the right and add a percent sign.
0.70 =
70.0%
= 70%

6. Student Practice 1:
Write 0.3 as a percent.
Method 1: Use pencil and paper. 3 10 30
100
Write the decimal as a fraction with a denominator of 100.
0.3 = =
Write the numerator with a percent sign.
= 30%
Method 2: Use mental math.
0.30 =
30.0%
Move the decimal point two places to the right and add a percent sign.
= 30%

7. Teacher Example 2: Writing Fractions as Decimals5 8
Write as a percent.
Method 1: Use pencil and paper. 5 8
= 5 ÷ 8
Use division to write the fraction as a decimal.
= 0.625
= 62.5%
Write the decimal as a percent.

8. Teacher Example 2 Continued:5 8
Write as a percent.
Method 2: Use mental math.
5   12.5
Write an equivalent fraction with a denominator of 100. =
Write the numerator with a percent sign.
= 62.5%

9. Student Practice 2: 3 5
Write as a percent.
Method 1: Use pencil and paper. 3 5
= 3 ÷ 5
Use division to write the fraction as a decimal.
= 0.60
= 60%
Write the decimal as a percent.

10. Student Practice 2 Continued:3 5
Write as a percent.
Method 2: Use mental math.
3   20
Write an equivalent fraction with a denominator of 100. =
Write the numerator with a percent sign.
= 60%

11. Teacher Example 3: Data Analysis Application
If 27 out of 50 people surveyed have the newspaper delivered to their home, what percent of these people have the newspaper delivered to their home? 27 50
Set up a ratio.
27 out of 50 =
Use division to write the fraction as a decimal.
= 27 ÷ 50
= 0.54
= 54%
Write the decimal as a percent.
54% of the people have the newspaper delivered to their home.

12. Teacher Example 3 Continued:
Check Use estimation to check that the answer is reasonable. 27 50 ≈
, or 50% 25 1 2
Because 50% is close to 54%, the answer is reasonable.

13. Write the numerator with a percent sign. = 22%
Student Practice 3:
If 11 out of 50 students surveyed have blue backpacks, what percent of the students have blue backpacks? 11 50 22
100 =
11 out of 50 =
Write the numerator with a percent sign.
= 22%
22% of the students have blue backpacks.

14. Student Practice 3 Continued:
Check Use estimation to check that the answer is reasonable. 22
100 ≈
, or 20% 20 1 5
Because 20% is close to 22%, the answer is reasonable.

15. Lesson Quiz
1. Write 0.65 as a percent.
65% 6 10
2. Write as a percent.
60%
3. If 36 out of 80 people surveyed have been on a boat, what percent of these people have been on a boat?
45%