Mental Math Estimate Sums and Differences

Estimate the sum by rounding to the nearest hundred

416 + 253

Gretchen drove 253 miles on Monday and 108 miles on Tuesday. To the nearest hundred, about how many miles did she drive on Monday and Tuesday?

237 fifth graders and 346 fourth graders went on a field trip. Estimate how many more fourth graders were on a field trip than fifth graders.

• 200 more

• 109 more

• 100 more

• 110 more

Eastfield college has 1,537 students. Richland college has 2,785. Rounding to the HUNDREDS place, approximately how many fewer students does Eastfield college have than Richland college.

• 1,300

• 1,200

• 1,100

• 1,500

A museum has 237 works of art on the first floor. The second floor has 349 works of art. The third floor has 219 works of art. About how many works of art in all? (Use greatest place value.)

• 800

• 700

• 750

• 660

Estimate the sum by rounding each number to the nearest whole number and then adding.

7.114 + 6.122

The sum is approximately

Estimate the sum by rounding each number to the nearest whole number and then adding.

6.17 + 4.7

The sum is approximately

Estimate the sum by rounding each number to the nearest whole number and then adding.

8.598 + 2.78

The sum is approximately

Estimate the sum by rounding each number to the nearest whole number and then adding.

3.78 + 7.249

The sum is approximately

Estimate the difference by rounding each number to the nearest whole number and then subtracting.

10.323 − 1.369

The difference is approximately