Title: Lesson 10-8
Author: mark_cameron
Last saved by: gtsmith
Company: McGraw-Hill

Lesson 7-8

Example 1 Estimate the Percent of a Number
Estimate 49% of 503.

49% is close to 50% or . Round 503 to 500.
 of 500 is 250.	 or half means to divide by 2.

So, 49% of 503 is about 250.

Example 2 Estimate the Percent of a Number
Estimate 80% of 58.

80% is .
Round 58 to 60 since it is divisible by 5.
 of 60 is 12.	 or 1 fifth means to divide by 5.
So,  of 60 is 4 × 12 or 48.
Thus, 80% of 58 is about 48.

Example 3 Real-World Example
MONEY   A sweatshirt that originally costs $23.99 is on sale for 25% off. If you have $20, would you have enough money to buy the sweatshirt?

To determine whether you have enough money to buy the sweatshirt, you need to estimate 75% of $23.99.

METHOD 1 Use a proportion.

75% =  and $23.99 ≈ $24
 = 	Write the proportion.

×6

	
  =  	Since 4 × 6 = 24, multiply 3 by 6.

×6

		
x = 18

METHOD 2 Use mental math.

75% =  and $23.99 ≈ $24
 of 24 is 18.

Since $18 is less than $20, you should have enough money.

Example 4 Standardized Test Practice
Favorite Season | Percent of Students
Spring | 9%
Summer | 62%
Autumn | 26%
Winter | 3%
MULTIPLE-CHOICE TEST ITEM   Miss Rogers surveyed her students regarding their favorite season of the year. Which is the most likely number of students out of 198 that would prefer autumn? 

A   15	B   26	
C   50	D   85

Read the Test Item
You need to estimate the number of students out of 198 that would prefer autumn. 
26% of the students chose autumn.

Solve the Test Item
26% is about 25% or . Round 198 to 200.
 of 200 is 50.

So, about 50 students would prefer autumn. The answer is C.