6th Grade Math Textbook, Fundamentals

Lesson 7-7 for exercise sets. &KDSWHU 

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Estimate.

1.Estimate 53% of 67. 2.About what percent of 3.3.9 is about 23.7% of

396 is 47? what number?

Estimate the percent of each figure that is shaded.

6.Discuss and Write Explain how you made your estimates for exercises 4 and 5.

A quick, reliable way to estimate with percents is to use

benchmark percents, such as 1%, 10%, 25%, 50%, and 75%.

• Estimate 6% of 39.
  39  40
  1% of 40 0.01 • 40 0.4

6% of 40 6 • 0.4 2.4

So 6% of 39 is about 2.4.

6% 6 • 1%.

Multiply 0.4

by 6.

1% 0.01.

Multiply by

0.01.

• Estimate 15% of $32.05.
  $32.05 $30
  15% 10% 5% Use 10% benchmark.
  10% of $30 0.1 • $30 $3.00

5% of $30 $3.00  2 $1.50

$3.00 $1.50 $4.50

So 15% of $32.05 is about $4.50.

Add the estimates

for 10% and 5%.

5 is half of 10,

so divide 10%

of $30 by 2.

Multiply mentally

by 0.1.

• About what percent of
  the bar is shaded?
  Think of dividing the bar
  into four equal parts. Then
  find a benchmark percent
  that is closest to the length
  of the shaded part.
  The shaded part is between 25% and 50%, but it
  is much closer to 25%. It is about 30% shaded.
  
  
  • About what percent
    of the container is
    full?
  
  
  
  

The container is filled

to about 350 mL, and

0.7 70%.

The container is about 70% full.

350

500

• About what percent of the figure is shaded?

Think of dividing the length into equal parts. Then

use benchmarks to estimate the percent shaded.

The figure is about 80% shaded.