Question

Use rounding to decide if the answer is reasonable.

Then find the answer to see if you were right.
1. 136-87 = 49
2.94-56 = 83
3.165+28 = 163

Answer 1

.1.

136-87 = 49

Rounding 136 to the nearest ten gives 140, and rounding 87 to the nearest ten gives 90. Subtracting these rounded values gives 50. Since 49 is close to 50, the answer is reasonable.

The actual answer is 49.

2.

94-56 = 83

Rounding 94 to the nearest ten gives 90, and rounding 56 to the nearest ten gives 60. Subtracting these rounded values gives 30. Since 83 is close to 30, the answer is not reasonable.

The actual answer is 38.

3.

165+28 = 163

Rounding 165 to the nearest ten gives 170, and rounding 28 to the nearest ten gives 30. Adding these rounded values gives 200. Since 163 is much less than 200, the answer is not reasonable.

The actual answer is 193.