Ring the gap before you calculate
The Short Answer
A missing number question gives you a calculation with a gap in it and another calculation that balances it. Ring the gap, work out the side that has all its numbers, write that total above the equals sign, and then fill the gap so its side makes the same total. The last step is checking that you wrote the gap rather than the total.
The method, in five steps
Ring the gap. Do the side that has all its numbers, one step at a time, writing each one down. Put the total above the equals sign. Fill the gap so its side makes that total. Check you have written the gap, and not the total.
That last step exists because it is where the marks actually go.
The gap does not always sit at the end
In the simplest versions it does. Eight sevens equals forty plus something — undo the last thing that happened, done.
In harder ones it moves:
It can be the divider. 96 ÷ ___ = 5 × 4 − 8. The other side makes twelve, and 96 divided by eight is twelve, so the gap is 8.
It can open the side. ___ × 6 = 100 − 52.
And it can be buried in the middle, with more still to come after it. That is the nasty one.
The diagram below shows the same example, with the wrong answer 10 tried out as well.
Which order do you work in?
The method says work one step at a time. Maths says brackets first, then multiply and divide, then add and subtract. When the two disagree, the maths rule wins.
Often they do not disagree. In many of these questions the times or the divide sits at the front of its side, so working along the line is already the right order. 72 ÷ 8 × 3 + 5 — nine, twenty-seven, thirty-two. Both rules, same answer.
But it does not have to sit at the front. In 3 + 6 × 8 the multiplication still comes first: 48, then 51. Working along the line would give 72, which is wrong.
So before you start a side: look for a bracket, then for a times or a divide, and do those first. Work left to right only among steps of the same rank.
The three-second check that saves the mark
Before writing anything down: look back at the gap you ringed. Is the number you are about to write the one that goes in that space? Or is it the total both sides make?
Then read the sum back with your answer in it. If it balances, it is right.
Where do pupils lose marks?
Writing the total. The biggest one, and it gets worse as pupils get faster.
Filling the gap from the first step. On a four-step side it is easy to work out seven sixes, feel like you have the total, and fill the gap from 42 rather than from the real total. Finish the side first.
Forgetting the tail — balancing at the gap when a step still follows it.
Doing the same operation instead of the opposite. Under pressure your hand does what it has just seen.
Try it yourself
Ring the gap before you calculate anything. Then read the sum back with your answer in it.
- 8 × 7 = 40 + ___
- 96 ÷ ___ = 5 × 4 − 8
- 30 − ___ − 3 = 4 × 5
- 9 × 7 − ___ = 6 × 8 + 3
- ___ × 6 = 100 − 52
- 16. The complete side makes 56, and 40 plus 16 is 56. Writing 56 is the commonest error on this whole type — that is the total, not the gap.
- 8. The right-hand side makes 12, and 96 divided by 8 is 12. Here the gap is the divider, which is why ringing it first matters.
- 7. The right-hand side makes 20. There is still a step after the gap, so the sum must reach 20 at the end, not at the gap: 30 − 7 is 23, and 23 − 3 is 20. Answering 10 means stopping at the gap and forgetting the tail.
- 12. The right-hand side makes 51, and 63 − 12 is 51. Two operations on the left, both of which must happen.
- 8. The right-hand side makes 48, and 48 divided by 6 is 8. The gap opens the side here, which reads oddly until you have seen it a few times.
How much practice does this type need at home?
Five a day, written, with the gap ringed before anything else happens. If the ring is not on the page the practice is not doing its job.
The single question worth asking afterwards is "what were you looking for?" — because a child who can answer that at the end of the sum has already avoided the mistake that matters.
Free: a Verbal Reasoning workbook
Questions across the Verbal Reasoning 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
What is the single commonest mistake here?
Writing the total instead of the gap. The working is perfect, the last line is wrong, and it happens to confident pupils more than to strugglers — because the faster you are, the less you look back at what was asked. Ringing the gap at the start and reading the sum back with your answer written in catches nearly all of it.
Where does the gap sit?
Anywhere. In the simplest versions it sits at the end of its side, so you undo the last thing that happened and are finished. In harder ones it can be the divider — 96 ÷ ___ = 12 — it can open the side, or it can be buried in the middle with more still to come after it. That last one is the nasty version, because the sum has to balance at the end rather than at the gap.
Does the order of operations matter in these?
It does, and it always wins. Brackets first, then multiplication and division, then addition and subtraction, and left to right only among steps of the same rank. In many of these sums the multiplication or division happens to sit at the front of its side, so working along the line gives the same answer — but that is not guaranteed. In 3 + 6 × 8 the multiplication still comes first, giving 51, even though it is printed second. Check for a bracket, then for a times or a divide, before working along the line.
Is written working really necessary for something this small?
It is faster, not just safer. Two small numbers in the margin cost about a second each, and they remove any chance of losing your place on a four-step side. A child holding a running total in their head is spending attention on remembering rather than on calculating.
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
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