Introduction
We can estimate the answer to an addition sum by rounding the numbers to the nearest hundred before we add.
Remember that if a number ends in 50 or above, it rounds up to the next hundred.
If a number ends in 49 or anything below, it rounds down to the previous hundred.
Example 1
Estimate the answer to the following sum by rounding the numbers to the nearest hundred and then adding.
326 + 567
Answer
326 + 567
↓ ↓
300 + 600 = 900
Example 2
Estimate the answer to the following sum by rounding the numbers to the nearest hundred and then adding.
150 + 415
Answer
150 + 415
↓ ↓
200 + 400 = 600
Remember that 150 rounds up to 200, 350 rounds up to 400, 250 rounds up to 300 etc.
Are you ready to try some questions now?
