Compare, then test
The Short Answer
Related numbers questions give you sets of three numbers where the middle one is made from the two on the outside, and ask you to find the missing one. Compare the middle number with the outer pair to narrow the rule down, test it on the second set, then apply it to the third. The hardest versions take two steps, and the number you reach after the first step is always printed as a wrong option.
Compare, then test
None of the arithmetic here will surprise anybody. The difficulty is entirely in choosing the right rule quickly, and in noticing when the rule takes two steps rather than one.
Compare the middle number with the two on the outside. Bigger than both means add or multiply. In between or smaller means take away or divide. Test the two that the size allows. Check it on set two. Then use it on set three.
Six rules, in a fixed order
Keep them in an order so you are never sitting there wondering what to try next.
- Adding.
- Multiplying — when the middle number is enormous compared with the outside ones.
- Taking away — bigger take smaller.
- Dividing — bigger divided by smaller.
- Halfway between.
- Two steps — combine the outer numbers, then do one more thing to the answer.
Rules one to five take a single step and most of them are visible in about ten seconds. Rule six is where the marks are actually lost.
When nothing one-step fits, combine first
The trap: an answer that is nearly right
On a two-step question, the number you get after the first step is always sitting there as one of the options. In that example it would be fifteen.
It is the most tempting wrong answer on the whole paper, because a pupil who picks it has not guessed. They have done real work and stopped one step early.
The four ways this type takes marks
Stopping after the first step. Every paper builds a wrong option out of exactly this.
Fitting a rule to set one and never testing set two. Five seconds, and it is the difference between a mark and a guess.
Subtracting or dividing the wrong way round. Always bigger take smaller, bigger divided by smaller, however they are printed — the examiner varies the order on purpose.
Ignoring the size of your own answer. If both visible middle numbers are smaller than their outer numbers and yours came out bigger, something is wrong, and you know that before checking any arithmetic.
Working quickly without losing accuracy
Write the two first-step results down, one under each middle number, on anything that might be two steps. Don't hold them in your head — the second step becomes visible rather than something to guess at.
Check on set two, always, even when you are certain.
And this question is worth one mark, the same as every other on the paper. If it has not opened up after a minute or so, mark it, move on, come back. The organised people are the fast ones; it is never the other way round.
Try it yourself
Compare the middle number with the outer two, test on both complete sets, then say your rule back in full before answering.
- 21 (32) 5 28 (90) 73 73 (___) 17
- 14 (11) 8 26 (19) 12 34 (___) 16
- 6 (17) 3 8 (39) 5 7 (___) 4
- In the first question, why is 56 the wrong answer?
- Both middle numbers you can see are smaller than their outer numbers, and your answer came out bigger. What does that tell you?
- 112. Difference then double: 21 − 5 is 16, doubled is 32; 73 − 28 is 45, doubled is 90. So 73 − 17 is 56, doubled is 112.
- 25. Add then halve: 14 + 8 is 22, halved is 11; 26 + 12 is 38, halved is 19. So 34 + 16 is 50, halved is 25.
- 27. Multiply then subtract one: 6 × 3 − 1 is 17; 8 × 5 − 1 is 39. So 7 × 4 − 1 is 27.
- Because it is the first step only. Fifty-six is the difference, and the rule does not stop there. It is the most tempting wrong answer on the paper, because a pupil who picks it has done real work and stopped early.
- That something is wrong, and you know it before checking any arithmetic. The size of your answer should behave like the sizes you can already see.
How much practice does this type need at home?
Little and often, and always with the rule said aloud in full. A child who answers "take away, then double" has understood the type. A child who answers "take away" is about to lose a mark to the halfway number.
Making them up is good practice too — pick a two-step rule, build three sets from it, and see whether someone else can find it.
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
How does my child narrow down which rule to try?
By comparing the middle number with the two outside it. Bigger than both means add or multiply — and if it is enormous compared with them, multiply. In between or smaller means subtract or divide. That comparison takes a second and removes half the options before any arithmetic happens, which is what makes the difference between a rule and a hunt.
What is a two-step rule and how do you spot one?
It combines the outer numbers and then does one more thing to the result — difference then double, add then halve, multiply then subtract one. You spot it by elimination: when nothing one-step fits, that is the information. Then do the first step on both complete sets and write the two answers under their middle numbers, and the second step becomes visible instead of something to guess at.
Why is the halfway number always among the options?
Because the examiner knows exactly which mistake is most likely. A pupil who does the first step and stops has done genuine work, so that number is the most tempting wrong answer on the page. The defence is to say your rule back in full before marking anything: not 'take away' but 'take away, then double'. If your answer came out of one operation, you have stopped early.
Why check the rule on the second set when the first one already worked?
Because one set is a coincidence and two is a rule. It takes about five seconds and it is the difference between a mark and a guess. That is precisely why the examiner prints two complete sets rather than one — the second set is there to be used.
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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