Assess Reasonableness of Decimal Sums and Differences

Round to the nearest HUNDRED to find the difference:

576.76 - 231.84

• 200

• 300

• 400

• 344.92

Estimating is finding a value that is CLOSE or APPROXIMATE to the actual value, but it's not exact.

• True

• False

Choose a good pair of compatible numbers to make finding the sum of 223.4 + 148.9 easier to add mentally.

• 200 + 100

• 223 + 149

• 225 + 150

• They're already compatible.

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

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

7.4 − 3.7

The difference is approximately

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

5.104 − 1.972

The difference is approximately