Find the place you are rounding to. Look only at the digit straight after it. If that digit is 5 or more, round up; if it is less than 5, round down. Don't round in steps from the end, and when a 9 rounds up it becomes 0 and carries 1 to the left, like 3.96 → 4.0.
Explore this idea with maths tools
Equal parts, equal wholes
2/4 = 4/8
Both bars are the same length. Find a division of the second bar that lines up exactly with the coloured edge.
Words to know
- round
- replace a number with a nearby simpler one
- decimal place
- a digit's position after the decimal point
- deciding digit
- the digit straight after the place you round to
Worked examples
Round 4.7 to the nearest whole number.
- 1.4.7 is between 4 and 5.
- 2.The next digit is 7, which is 5 or more, so round up.
= 5
Round 2.46 to the nearest whole number.
- 1.2.46 is between 2 and 3.
- 2.The next digit is 4, so round down. Don't round 6 first.
= 2
Round 3.96 to one decimal place.
- 1.3.96 is between 3.9 and 4.0.
- 2.The next digit is 6, so round up: 9 tenths become 10 tenths, which carries to the ones.
= 4.0
For parents
Method: Look at the next digit
What to say: Which place are you rounding to? What is the very next digit?
Common mistakes:
- When a 9 rounds up, writes 10 in that place instead of carrying (3.96 → 3.10).
- Rounds one digit at a time from the right (2.46 → 2.5 → 3) instead of looking only at the next digit.
- Cuts off the extra digits without rounding up when the next digit is 5 or more.
- Always rounds up to the next value, even when the next digit is less than 5.
- Rounds to one more decimal place than asked (or leaves the number unrounded).