Odd one out questions are answered by finding what four of the five share, not by finding what one of them does differently. That sounds like the same thing. It is not, and the difference is worth several marks.
Non-verbal and spatial reasoning together carry 25% of the marks, according to the partnership entrance test page. It is also the one section nothing in primary school prepares a child for, which is why almost every child starts from zero here.
Look for the rule the four obey
A child who hunts for the odd shape finds five candidates, because every shape differs from the others in some way. A child who hunts for the shared rule finds one answer.
- Take the first two shapes and ask what they have in common.
- Test that against the third. If it holds, you may have the rule.
- Test it against all five. Exactly four should obey it.
- If more than one breaks the rule, your rule is wrong. Find another.
That last step is the useful one. It gives a child a way of knowing they are wrong, rather than guessing and hoping.
The rules that come up
| Check | Example of the shared rule |
|---|---|
| Number of sides | All have an even number of sides |
| Number of elements | All contain exactly three dots |
| Shading | The shaded part is always the largest part |
| Symmetry | All have a line of symmetry |
| Relationship between parts | The small shape is always inside the large one |
| Right angles | All contain at least one right angle |
| Lines crossing | No lines cross, in four of them |
Run down that list when nothing is obvious. Most odd one out questions in this test use one of these, and having a list is far better than staring.
Analogies: A is to B as C is to what?
Analogies look different and use the same muscle. The question gives you a transformation and asks you to apply it.
- Work out exactly what happened between A and B. Be specific. Not "it changed" but "it rotated a quarter turn clockwise and the shading moved to the inner shape".
- Say the rule out loud, or write it down. A vague rule produces a wrong answer.
- Apply it to C and predict what you expect.
- Only then look at the options.
The commonest error is settling for half the rule. If two things changed between A and B and a child only notices one, several options will match that half, and they will pick the wrong one with confidence.
Work backwards, not forwards
Both of these types reward elimination over selection, and that is an unfamiliar habit for a child.
At school you work forwards towards an answer. Here you often get further by ruling options out. Cross off what cannot be right, in pencil, and the answer is frequently the last one standing rather than the one that looked right first.
See our guide to series and sequences and our guide to non-verbal reasoning.
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Children have to be taught to work backwards
Odd one out and sequences are the two I find hardest to teach in the whole non-verbal section. The reason is that students are looking for minute details within the question to work out what the answer is, and then they have to negate or eliminate the options to come to the right solution.
That is the part that is genuinely unfamiliar. Everywhere else in their schooling a child works forwards towards an answer. Here they often have to work backwards and rule things out, and almost nobody arrives at that habit on their own.
So teach the elimination explicitly. Pencil, cross off what cannot be right, and accept that the answer is often simply the last one standing rather than the one that looked right at first glance. Once a child trusts that process they stop panicking on these, and the marks follow.
Mushtaque Ahmed, Founder of GrammarPath and Bright Mentors
Frequently asked questions
How do you solve odd one out questions in the 11+?
Look for the rule that four of the five shapes share, rather than hunting for the odd one. Test a candidate rule against all five: exactly four should obey it, and if more than one breaks it your rule is wrong and you need another.
What rules come up in odd one out questions?
Commonly the number of sides, the number of elements such as dots, the shading, whether the shape has a line of symmetry, the relationship between an inner and outer shape, the presence of right angles, and whether lines cross. Running down that list beats staring at the picture.
How do you answer non-verbal analogy questions?
Work out precisely what happened between the first shape and the second, state the rule in full rather than vaguely, apply it to the third shape and predict the answer before looking at the options. The commonest error is noticing only half of a two-part rule.
Why does my child pick the wrong answer confidently on analogies?
Usually because they spotted only part of the transformation. If two things changed and the child noticed one, several options will match that half, so they choose one and feel certain. Saying the whole rule out loud before looking at the options prevents it.
Should my child eliminate or select in non-verbal reasoning?
Eliminate. At school children work forwards towards an answer, but these questions reward ruling options out in pencil until one remains. It is an unfamiliar habit and it needs teaching deliberately rather than being assumed.