Round once, from the right column: rounding in the 11+
The Short Answer
Rounding asks your child to find the column the question names, look exactly one digit to its right, and decide once. Five or more rounds up, less than five rounds down, and everything beyond that one decider is irrelevant. The routine is the same at any size and on either side of the decimal point: underline, decide, zero, once.
What is a rounding question?
Rounding asks your child to give a number to a stated degree of accuracy: to the nearest ten, the nearest thousand, or to a given number of decimal places.
It is one of the first things the 11+ tests and one of the easiest places to lose a mark, because the method is short enough to feel like it does not need doing properly. Here is the idea the whole topic hangs on, and it is worth saying out loud at the kitchen table: 449 does not round to 500.
How do you teach the method?
Four steps, always in the same order, whatever the size of the number and whichever side of the decimal point it sits on. We teach it as underline, decide, zero, once.
Underline the digit in the column the question names. For large numbers, group the digits in threes first and name the column out loud — this is where most wrong answers begin.
Find the decider: the digit immediately to the right of the underlined one. Exactly one place right. Nothing beyond it counts, however large it looks.
Five or more rounds up, less than five rounds down. Then fill every column to the right with zeros, keeping the place value the question asked for.
Decide once. There is no second round, no working up through the columns, no stages.
Can you show me a worked example?
Why is rounding in stages wrong?
Because there is only one decider, and rounding twice invents a second one.
Take 449 to the nearest hundred. The reasoning that goes 449 rounds to 450, and 450 rounds to 500 feels careful — it looks like extra work being done properly. It produces the wrong answer.
The question asks for the nearest hundred, so the decider is the tens digit: 4. Four is less than five, so the number rounds down. The answer is 400. The 9 on the end sits beyond the decider and never had a vote.
This is the single most common way marks are lost on this topic, and it is worth being blunt about at home, because the mistake comes from trying harder rather than from not understanding.
Where do pupils lose marks?
Five traps, and the examiner sets every one of them deliberately.
| Trap | What it looks like | The fix |
|---|---|---|
| Wrong column | "Nearest ten thousand" read as "nearest ten" | Group in threes, name the column aloud |
| Rounding in stages | 449 → 450 → 500 | One decider, one decision |
| Losing the size | 46 218 to the nearest thousand written as 46 | Sense-check against the original |
| Dropping the trailing zero | 79.96 to 1 d.p. written as 80 | Show the number of places asked for |
| Rounding in the wrong unit | Rounding kilograms when asked for grams | Convert first, round, convert back |
The third one is worth dwelling on. A child who writes 46 has done the rounding correctly and then thrown away the place value. A quick look back at the original number catches it every time.
Try it yourself
Work each one through in full. On the last two, write your working down rather than trying to hold it in your head.
- Round 384 507 to the nearest 100 000.
- Round 0.4629 to 2 decimal places.
- Round 8 963 to the nearest 100.
- A number rounded to the nearest 10 is 54 780. What is the smallest whole number it could be?
- Round 27.856 kg to the nearest 10 g.
- 400 000. The hundred thousands digit is 3 and the decider is 8. Eight is five or more, so the 3 becomes 4. Group the number in threes before anything else, or it is easy to name the wrong column.
- 0.46. The hundredths digit is 6 and the decider is 2. Two is less than five, so it stays. The 9 on the end never had a vote — it sits beyond the decider.
- 9 000. The hundreds digit is 9 and the decider is 6, so rounding up carries into the thousands. A nine rounding up is normal; let the carry ripple left.
- 54 775. It rounds up to 54 780, while 54 774 would round down to 54 770. The smallest is always the rounded value minus half the step.
- 27.86 kg. Convert first: 27.856 kg is 27 856 g. To the nearest 10 g the tens digit is 5 and the decider is 6, so it rounds up to 27 860 g, which is 27.86 kg. Rounding in the wrong unit gives the wrong answer every time.
How much practice does this type need at home?
Ten minutes, three times a week, for a fortnight is usually enough to make the routine automatic — and automatic is the goal, because rounding rarely appears on its own. It turns up as the final step of a longer question, when your child is tired and moving quickly.
After that, the practice worth doing is mixed: a few rounding questions among other topics, so the routine has to be recalled rather than repeated. If your child is still hesitating after a fortnight, it is nearly always the column rather than the decision that is the problem. Go back to naming the column out loud before anything else, and the rest usually follows.
Free: a Maths workbook
Questions across the Maths question types, with the method printed at the top and full answers at the back. One workbook for the whole strand, not a sheet per question type.
Frequently Asked Questions
Why is 449 to the nearest hundred 400 and not 500?
Because there is only ever one decider. To round to the nearest hundred, the decider is the tens digit — the 4. Four is less than five, so the number rounds down to 400. What children do instead is round twice: 449 becomes 450, and 450 becomes 500. The 9 on the end is beyond the decider, so it takes no part in the decision at all. One decider, one decision, and never in stages.
What does 'to two decimal places' actually mean?
Two decimal places means the nearest hundredth, and it also means the answer must show exactly two digits after the point. Not one, not three. Children who round 0.3462 correctly and write 0.3 lose the mark for the presentation rather than the arithmetic, which is a frustrating way to lose one. One place is the nearest tenth, two the nearest hundredth, three the nearest thousandth.
What happens when the digit being rounded is a nine?
It carries, exactly as it does in column addition. Rounding 79.96 to one decimal place, the tenths digit is 9 and the decider is 6, so it rounds up — but there is no such thing as ten tenths, so the tenths become 0 and the units go up by one, giving 80.0. Keep the point zero: the question asked for one decimal place. Whole numbers behave identically, so 6 970 to the nearest hundred is 7 000.
My child rounds correctly but still gets measures questions wrong. Why?
Almost always because they rounded before converting. If a question gives a number in kilograms and asks for the nearest ten grams, the number has to be turned into grams first, rounded there, and turned back. Convert, round, convert back — in that order. Rounding in the wrong unit produces a wrong answer however good the rounding was.
How is this tested if it looks so simple?
Usually by hiding it inside something else. A common form gives five options and asks which of them equals a given number, so your child has to round five times rather than once. There is no shortcut on that: all five have to be worked out and written down. Rounding also turns up inside multi-step questions, where it is the last step and the easiest one to rush.
Sources
- GL Assessment — 11+ familiarisation materials and question type descriptions Published 2025.
- Clever Clogs Academy — our own Year 4 and Year 5 lesson records, Winslow Published September 2025 to July 2026.
We are not affiliated with, endorsed by or connected to GL Assessment or Buckinghamshire Council. Test arrangements change; always check the council's own pages for the current year's dates.
We Teach This Method Every Week in Winslow
Groups of no more than six pupils with two qualified teachers, in person or online. Come and see a session before you decide.