8-1 Percent and Estimation

1
8-1 Percent and Estimation

• Pages 334-337
• Indicator(s)? N8 Develop and analyze algorithms
  for computing with percents and demonstrate
  fluency in use.

2
To estimate the percent of a number

• you can use a fraction or a multiple of 10 or
  1.
• Example 1
• Use a fraction to estimate 77 of 800.
• 77 is about 75 or .
• 77 of 800 800
• 600
• So, 77 of 800 is about 600.

3
Percents greater than 100

• Example 2
• Percents greater than 100. Estimate 137 of
  50. 137 is more than 100,
• so 137 is going to be greater than 50.
• 137 is about 140.
• 140 of 50 (100 50) (40 50)
• (1 50) ( 50)
• 50 20 70
• So, 137 of 50 is about 70.

4
Percents less than 1

• Example 3
• Percents less than 1. Estimate 0.5 of 692.
• 0.5 is half of 1.
• 692 is about 700
• To find 1 of 700, change to decimal and
  multiply.
• 1 0.01 SO 0.01 700
• 7
• One half of 7 is 7 or 3.5
• So, 0.5 of 692 is about 3.5.

5
Estimate by using 10

• Example 4
• Estimate 59 of 500.
• 10 of 500 is 50.
• 59 is about 60.
• 60 of 500 is 6 10.
• 6 50 300
• So, 59 of 500 is about 300.

6
8-1 b

• Page 338-339
• 1-13 all