1. Estimate with Percents
6-2
Estimate with Percents
Course 2
Warm Up
Problem of the Day
Lesson Presentation

2. Estimate with Percents
Course 2
6-2
Estimate with Percents
Warm Up
Write each percent as a fraction and as a decimal.
1. 75%
2. 10%
3. 32%
4. 17% 34
, 0.75
, 0.1 10 1
, 0.32 25 8
, 0.17
100 17

3. Estimate with Percents
Course 2
6-2
Estimate with Percents
Problem of the Day
You are biking to the library. When you are 75% of the way there, you realize you forgot a book. So you turn around
and head back. When you are of the way back you realize you don’t need the book, so you turn around again and bike 3.2 miles back to the library. How far do you live from the library? 1 3
6.4 miles

4. Estimate with Percents
Course 2
6-2
Estimate with Percents
Learn to estimate percents.

5. Estimate with Percents
Course 2
6-2
Estimate with Percents
The table shows common percents and their fraction equivalents. You can use fractions to estimate the percent of a number by choosing a fraction that is close to a given percent.
Percent
Fraction
33 % 1 3
66 % 2 3
10%
20%
25%
50% 1 10 1 5 1 4 1 3 1 2 2 3

6. Additional Example 1: Using Fractions to Estimate Percents
Course 2
6-2
Estimate with Percents
Additional Example 1: Using Fractions to Estimate Percents
Use a fraction to estimate 27% of 63. 1 4
Think: 27% is about 25% and
25% is equivalent to .
27% of 63 
· 63 1 4 1 4
Change 63 to a compatible number. 
· 60
 15
Multiply.
27% of 63 is about 15.
Compatible numbers are close to the numbers in the problem and are used to do math mentally.
Remember!

7. Estimate with Percents
Course 2
6-2
Estimate with Percents
Try This: Example 1
Use a fraction to estimate 48% of 91. 1 2
Think: 48% is about 50% and
50% is equivalent to .
48% of 91 
· 91 1 2 1 2 
· 90
Change 91 to a compatible number.
 45
Multiply.
48% of 91 is about 45.

8. Additional Example 2: Consumer Math Application
Course 2
6-2
Estimate with Percents
Additional Example 2: Consumer Math Application
Cary earns $9.88 per hour. He gets a bonus of 50% for each hour he works overtime. About how much is he paid per hour for overtime?
First find the bonus for each hour of overtime. 1 2 1 2
50% of $9.88 =
· $9.88
Think: 50% is equivalent to . 1 2
· $10
Change $9.88 to a compatible number. 
 $5
Multiply.
The bonus is approximately $5. Since $10 + $5 = $15,
he earns about $15 for each hour he works overtime.

9. Insert Lesson Title Here
Course 2
6-2
Estimate with Percents
Insert Lesson Title Here
Try This: Example 2
Billy has a job assembling office furniture. He is paid $9.20 for each unit completed. If he completes more than 10 units a week he is paid an additional 25% per unit. How much is he paid for each unit above 10.
First find the additional amount earned for each unit above 10. 1 4
25% of $9.20 =
· $9.20 1 4
Think: 25% is equivalent to . 1 4
· $9
Change $9.20 to a compatible
number. 
 $2.25
Multiply.
The bonus for each extra unit is approximately $2.25. Since
$9 + $2.25 = $11.25, he earns about $11.25 for each extra unit.

10. 1% of 45 = . 45 . 10% of 45 = 45 . . 6-2 Estimate with Percents
Course 2
6-2
Estimate with Percents
Another way to estimate percents is to find
1% or 10% of a number. You can do this
by moving the decimal point in the number.
1% of 45 = . 45 .
10% of 45 = 45 . .
To find 1% of a number, move the decimal point two places to the left.
To find 10% of a number, move the decimal point one place to the left.

11. Additional Example 3A: Estimating with Simple Percents
Course 2
6-2
Estimate with Percents
Additional Example 3A: Estimating with Simple Percents
Use 1% or 10% to estimate the percent of each number.
A. 4% of 18
18 is about 20, so find 4% of 20.
1% of 20 = 20. .
4% of 20 = 4 · 0.2 = 0.8
4% equals 4 · 1%.
4% of 18 is about 0.8.

12. Additional Example 3B: Estimating with Simple Percents
Course 2
6-2
Estimate with Percents
Additional Example 3B: Estimating with Simple Percents
Use 1% or 10% to estimate the percent of each number.
B. 29% of 80
29% is about 30, so find 30% of 80.
10% of 80 = 80. .
30% of 80 = 3 · 8.0 = 24.0
30% equals 3 · 10%.
29% of 80 is about 24.

13. Estimate with Percents
Course 2
6-2
Estimate with Percents
Try This: Example 3A
Use 1% or 10% to estimate the percent of each number.
A. 5% of 14
14 is about 15, so find 5% of 15.
1% of 15 = 15. .
5% of 15 = 5 · 0.15 = 0.75
5% equals 5 · 1%.
5% of 14 is about 0.75.

14. Estimate with Percents
Course 2
6-2
Estimate with Percents
Try This: Example 3B
Use 1% or 10% to estimate the percent of each number.
B. 21% of 60
21% is about 20, so find 20% of 60.
10% of 60 = 60. .
20% of 60 = 2 · 6.0 = 12.0
20% equals 2 · 10%.
21% of 60 is about 12.

15. Additional Example 4: Consumer Math Application
Course 2
6-2
Estimate with Percents
Additional Example 4: Consumer Math Application
Tim spent $58 on dinner for his family. About how much money should he leave for a 15% tip?
Since $58 is about $60, find 15% of $60.
15% = 10% + 5%
Think: 15% is 10% + 5%.
10% of $60 = $6
5% is of 10% so divide $6 by 2. 1 2
5% of $60 = $6 ÷ 2 = $3
$6 + $3 = $9
Add the 10% and 5% estimates.
Tim should leave about $9 for a 15% tip.

16. Estimate with Percents
Course 2
6-2
Estimate with Percents
Try This: Example 4
Amanda spent $12 on a hair cut. About how much money should she leave for a 15% tip.
Since $12 is about $10, find 15% of $10.
15% = 10% + 5%
Think: 15% is 10% + 5%.
10% of $10 = $1
5% is of 10% so divide $1 by 2. 1 2
5% of $10 = $1 ÷ 2 = $0.50
$1 + $0.50 = $1.50
Add the 10% and 5% estimates.
Amanda should leave about $1.50 for a 15% tip.

17. Estimate with Percents Insert Lesson Title Here
Course 2
6-2
Estimate with Percents
Insert Lesson Title Here
Lesson Quiz
Use a fraction to estimate the percent of each number.
1. 48% of 72
2. 26% of 80
Use 1% or 10% to estimate the percent of each number.
3. 4% of 220
4. 19% of 75
5. Mr. and Mrs. Dargen spend $46.25 on a meal. About how much should they leave for a 15% tip?
Possible answers: 36 20
Possible answers:
8.8 15 $7