Estimating With Percents 6-2

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. Fraction Percent 10%20%25%50% 33 % %

Use a fraction to estimate 27% of 63. Additional Example 1: Using Fractions to Estimate Percents 27% of 63  1414 · 63  1414 · 60  15 27% of 63 is about 15. Compatible numbers are close to the numbers in the problem and help you use mental math to find a solution. Remember! Think: 27% is about 25% and 25% is equivalent to Change 63 to a compatible number. Multiply.

Use a fraction to estimate 48% of 91. Check It Out: Example 1

Tara’s T’s is offering 2 T-shirts for $16, while Good-T’s is running their buy one for $9.99, get one for half price sale. Which store offers the better deal? Additional Example 2: Consumer Math Application First find the discount price for 2 t-shirts at Good T’s. 50% of $9.99 = 1212 · $9.99  1212 · $10  $5 The second shirt cost approximately $5. Since $10 + $5 = $15, the 2 T-shirts for $15 at Good-T’s is the better deal. Think: 50% is equivalent to. 1 2 Change $9.99 to a compatible number. Multiply.

Check It Out: Example 2 Billy’s Office Supply Store is offering 25% off a leather notebook, originally priced at $9.75. K’s Office Supply Store offers the same notebook, not on sale, at $7.00. Which store offers the better deal?

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 = 10% of 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

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

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

Use 1% or 10% to estimate the percent of each number. Check It Out: Example 3A 5% of 14

Use 1% or 10% to estimate the percent of each number. Check It Out: Example 3B 21% of 60

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

Amanda spent $12 on a hair cut. About how much money should she leave for a 15% tip? Check It Out: Example 4