1. Estimating With Percents
COURSE 3 LESSON 6-2
Estimate 74% of 158 using decimals.
74%
0.75
Use a decimal that is close to 74%.
158
160
Round 158 to a number that is compatible with 0.75.
74% of 158
0.75 of 160
= 0.75 • 160
Multiply to find 0.75 of 160.
= 120
Simplify.
6-2

2. Estimating With Percents
COURSE 3 LESSON 6-2
Dion is saving for a coat that costs $ She has saved 45% of the cost. Estimate how much she has saved.
What you think
The coat costs about $60.
I know 50% of 60 equals of 60, or 30. Since 5% is one-tenth of 50%, then 5% of 60 is one-tenth of 30, which is 3. So, the amount Dion has saved is about $30 minus $3, which is $27. 1 2
6-2

3. Estimating With Percents
COURSE 3 LESSON 6-2
(continued)
Why it works
50% of 60 = 0.5 • 60
To find 50% of a number, multiply the number by 0.5.
= 30
Simplify.
5% of 60 = (50% of 60)
5% of a number is one-tenth of 50% of that number. 1 10
= (30) 1 10
Substitute.
= 3
Simplify.
45% of 60 = 30 – 3
45% = 50% – 5%
= 27
Simplify.
So, 45% of $59.95 is about $27.
6-2