1. Estimating with Percents Mrs. Herron

2. I can… Estimate percents using compatible numbers Estimate percents using compatible numbers This table shows common percents and their fraction equivalents. You can estimate the percent of a number by substituting a fraction that is close to a given percent. This table shows common percents and their fraction equivalents. You can estimate the percent of a number by substituting a fraction that is close to a given percent. Percent10%20%25%33 1/3%50%66 2/3% Fraction1/101/5¼1/3½2/3

3. Compatible Numbers Compatible Numbers are close to the numbers in a problem and help you use mental math to find a solution. Compatible Numbers are close to the numbers in a problem and help you use mental math to find a solution. Use a fraction to estimate 48% of 79. 48% of 79 ~ ½ x 79 48% of 79 ~ ½ x 79 ~ ½ x 80 ~ ½ x 80 ~ 40 ~ 40 48% of 70 is about 40.

4. Story Problem example Cam’s Sports is offering 20% off a basketball that costs $19.99. The same basketball costs $14.99 at Hoops Haven. Which store offers the better deal? Cam’s Sports is offering 20% off a basketball that costs $19.99. The same basketball costs $14.99 at Hoops Haven. Which store offers the better deal? First find the discount on the basketball at Cam’s Sports. First find the discount on the basketball at Cam’s Sports. 20% of $19.99 = 1/5 x $19.99 20% of $19.99 = 1/5 x $19.99 ~ 1/5 x $20 ~ 1/5 x $20 ~ $4 ~ $4 The discount is approximately $4. Since $20 - $4 = $16, the $14.99 basketball at Hoops Haven is the better deal. The discount is approximately $4. Since $20 - $4 = $16, the $14.99 basketball at Hoops Haven is the better deal.

5. Another Way 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. 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; 45.0 1% of 45; 45.0 =0.45 To find 1% of a number, move the decimal point two places to the left. =0.45 To find 1% of a number, move the decimal point two places to the left. 10% of 45 ; 45.0 10% of 45 ; 45.0 =4.5 To find 10% of a number, move the decimal point one place to the left. =4.5 To find 10% of a number, move the decimal point one place to the left.

6. Estimating with Simple Percents Use 1% or 10% to estimate the percent of each number. Use 1% or 10% to estimate the percent of each number. 3% of 59 3% of 59 59 is about 60, so find 3% of 60 59 is about 60, so find 3% of 60 1% of 60 = 60.0 = 0.60 1% of 60 = 60.0 = 0.60 3% of 60 = 3 x 0.60 = 1.8 3% of 60 = 3 x 0.60 = 1.8 3% of 59 is about 1.8 3% of 59 is about 1.8

7. Write a Convincing Argument Using the steps write a convincing argument about the following question: Using the steps write a convincing argument about the following question: Explain two ways to estimate 51% of 88. Explain two ways to estimate 51% of 88.

8. Homework Practice Page C and finishing the Convincing Argument. Practice Page C and finishing the Convincing Argument.