Learn on PengienVision, Mathematics, Grade 6Chapter 6: Understand and Use Percent

Lesson 4: 6-4 Estimate to Find Percent

In this Grade 6 lesson from enVision Mathematics Chapter 6, students learn how to estimate the percent of a number using three strategies: equivalent fractions, rounding, and compatible numbers. The lesson covers Common Core standard 6.RP.A.3c and guides students through real-world problems, such as approximating 46% of 500 by recognizing that 46% is close to 50%, which equals one-half. By the end of the lesson, students can choose the most efficient estimation method based on the numbers given.

Section 1

Estimating with Benchmark Percents

Property

To estimate the percent of a number, round the percent to a nearby benchmark percent that is easy to calculate mentally. Common benchmark percents include 10%=11010\% = \frac{1}{10}, 25%=1425\% = \frac{1}{4}, 50%=1250\% = \frac{1}{2}, and 75%=3475\% = \frac{3}{4}.

Examples

Section 2

Rounding Both the Percent and the Number

Property

To estimate the percent of a number, you can round both the percent and the number to create a simpler problem. First, round the percent to a nearby benchmark percent (like 10%10\%, 25%25\%, or 50%50\%). Then, round the whole number to a compatible number that is easy to calculate with.

Examples

  • To estimate 24%24\% of 8181, round 24%24\% to 25%25\% and 8181 to 8080. The estimate is 25%25\% of 8080, which is 14×80=20\frac{1}{4} \times 80 = 20.
  • To estimate 48%48\% of 197197, round 48%48\% to 50%50\% and 197197 to 200200. The estimate is 50%50\% of 200200, which is 12×200=100\frac{1}{2} \times 200 = 100.

Explanation

This estimation strategy makes calculations much simpler by using numbers that are easier to work with. By rounding the percent to a common benchmark and the whole number to a compatible value, you can often perform the calculation mentally. This method provides a reasonable approximation of the actual answer without needing a calculator. The goal is to choose rounded values that make the multiplication straightforward.

Lesson overview

Expand to review the lesson summary and core properties.

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Section 1

Estimating with Benchmark Percents

Property

To estimate the percent of a number, round the percent to a nearby benchmark percent that is easy to calculate mentally. Common benchmark percents include 10%=11010\% = \frac{1}{10}, 25%=1425\% = \frac{1}{4}, 50%=1250\% = \frac{1}{2}, and 75%=3475\% = \frac{3}{4}.

Examples

Section 2

Rounding Both the Percent and the Number

Property

To estimate the percent of a number, you can round both the percent and the number to create a simpler problem. First, round the percent to a nearby benchmark percent (like 10%10\%, 25%25\%, or 50%50\%). Then, round the whole number to a compatible number that is easy to calculate with.

Examples

  • To estimate 24%24\% of 8181, round 24%24\% to 25%25\% and 8181 to 8080. The estimate is 25%25\% of 8080, which is 14×80=20\frac{1}{4} \times 80 = 20.
  • To estimate 48%48\% of 197197, round 48%48\% to 50%50\% and 197197 to 200200. The estimate is 50%50\% of 200200, which is 12×200=100\frac{1}{2} \times 200 = 100.

Explanation

This estimation strategy makes calculations much simpler by using numbers that are easier to work with. By rounding the percent to a common benchmark and the whole number to a compatible value, you can often perform the calculation mentally. This method provides a reasonable approximation of the actual answer without needing a calculator. The goal is to choose rounded values that make the multiplication straightforward.