The idea
Round a decimal by inspecting the digit immediately to the right of the required place.
Follow these steps
- Underline the rounding digit.
- Use the next digit: 5 or more rounds up; 4 or less stays.
- Remove digits beyond the required place and retain the correct unit.
See the method in action
Example 1
Two lengths are 4.27 m and 5.2 m. Add them, then round the total to 1 decimal place.
- Add first: 4.27 + 5.2 = 9.47.
- The next digit is 7, so the rounded total is 9.5 m.
Example 2
A number with exactly 3 decimal places rounds to 14.03 at 2 decimal places. What is the smallest possible number?
- The halfway point below 14.03 is 14.025.
- This rounds upwards to 14.03; every smaller permitted number rounds to 14.02 or less.
A useful shortcut
Remove digits beyond the required place and retain the correct unit.
Watch out for these
Three fresh questions
Ready to check the method? You will get three fresh, validated questions.