8-1 Percent and Estimation Pages Indicator(s) N8 Develop and analyze algorithms for computing with percents and demonstrate fluency in use.
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 % is about 75% or. 77% of 800 ≈ × 800 ≈ 600 So, 77% of 800 is about 600.
Example 2 Percents greater than 100. Estimate 137% of % is more than 100%, so 137% is going to be greater than % is about 140%. 140% of 50 = (100% × 50) + (40% × 50) = (1 × 50) + ( × 50) = = 70 So, 137% of 50 is about 70. Percents greater than 100
Example 3 Percents less than 1. Estimate 0.5% of % 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. Percents less than 1
Example 4 Estimate 59% of % of 500 is % is about 60%. 60% of 500 is 6 × 10%. 6 × 50 = 300 So, 59% of 500 is about 300. Estimate by using 10%
8-1 b Page #1-13 all