Beginner · 10 min
Rounding and estimating
Choose a useful level of precision and check whether an answer is reasonable.
Round to a place
Look at the digit immediately to the right of the rounding place. For positive numbers, 5 or more rounds up; otherwise keep that place unchanged.
Worked example
3,746 rounded to the nearest hundred is 3,700.
Estimate before calculating
Round quantities to convenient values for a quick estimate. The estimate is a check, not an exact replacement when precision matters.
Worked example
19 × 31 is close to 20 × 30 = 600.
Check a shopping total
- Estimate the cost of 6 items priced at 9.80 each.
- Calculate the exact total and compare it with your estimate.