Question

How to Estimate adding decimals

Answer 1

To estimate in the proccess of adding decimals, round the decimal to the nearest whole number. Then, add those two whole numbers, which should be close to your exact answer.

Example:

5.42+7.92

5.42-->5

7.92-->8

5+8=13

Exact Answer:

1

7.92

5.42

+_________

13.34

The answer 13.34 is close to the estimate of 13 so the answer is reasonable.

Answer 2

Write down the numbers, one under the other, with the decimal points lined up. Put in zeros so the numbers have the same length (see below for why that is OK) Then add using column addition, remembering to put the decimal point in the answer.