Series questions are solved by checking one variable at a time, in a fixed order, rather than looking at the whole picture and hoping.
These are among the hardest non-verbal questions to teach, because the change is often tiny and there may be two or three things changing at once.
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.
The five things that can change
Almost every series in this test moves one or more of five variables. Check them in this order, every time, and write the pattern down rather than holding it in your head.
| Check | Ask | Typical pattern |
|---|---|---|
| 1. Number | How many of each thing? | Goes up by one each step |
| 2. Size | Is anything growing or shrinking? | Alternates large and small |
| 3. Shading | What is black, white or striped? | Shading moves round the shape |
| 4. Rotation | Has anything turned? | A quarter turn each step |
| 5. Position | Has anything moved? | A dot moves one corner clockwise |
Counting first is deliberate. It is the quickest check and it settles a surprising number of questions on its own.
When two things change at once
The harder series move two variables together: the shape rotates and the shading advances, or a dot moves round and an extra line appears.
Do not try to see both. Work out the first pattern completely, write it down, then go back to the start and work out the second. Treating one series as two simple series is the whole technique.
Then predict the answer before looking at the options. A child who reads the options first will talk themselves into one of them.
Matrices and grids
A matrix is a series folded into a square, and the same method works. The rule usually runs across each row and separately down each column.
- Read the top row left to right and work out what happens from box to box.
- Check that rule against the second row. If it holds, you have it.
- Then read the columns, because the missing box answers to both its row and its column.
- Use the column as your check on the answer the row gave you.
Having two independent routes to the same answer is what makes matrices more reliable than straight series, once a child knows to use both.
Habits that save marks
- Write the pattern in the margin. "+1 dot, turn 90" takes three seconds and stops a child losing the thread.
- Predict before reading the options.
- If stuck, count something. Sides, dots, lines, enclosed spaces.
- Eliminate rather than select. Rule out the three that are clearly wrong and choose between two.
- Move on. Sections are individually timed and a minute lost here cannot be made back later.
See our guide to odd one out and analogies, which uses the same elimination habit.
See where your child stands today
Timed sections in the GL Assessment format, marked instantly, with a topic-by-topic breakdown. No sign-up to start.
This is one of the two hardest to teach
In terms of which topics are genuinely difficult, I find odd one out and sequences are the hardest to teach. Not because the ideas are complicated, but because 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 arrive at the right one.
That is a different mental habit from most of what a child does at school, where you work forwards towards an answer. Here you often work backwards, ruling things out. It takes deliberate teaching.
What helps is slowing the child down and giving them a fixed order to check things in, so they are not scanning the picture hoping something jumps out. Count first. Then size, shading, rotation, position. Write it down. The children who improve fastest on these are the ones who stop trying to see the answer and start working through a list.
Mushtaque Ahmed, Founder of GrammarPath and Bright Mentors
Frequently asked questions
How do you solve non-verbal reasoning series questions?
Check one variable at a time in a fixed order: number, size, shading, rotation, then position. Write the pattern down in the margin rather than holding it in your head, and predict the answer before looking at the options.
What should my child check first in a series question?
Count something. Number is the quickest check available and it settles a surprising proportion of questions on its own, which is why it comes before size, shading, rotation and position in the order.
What if two things change at once in a series?
Treat it as two separate series. Work out the first pattern completely and write it down, then go back to the beginning and work out the second. Trying to track both at the same time is what makes these questions feel impossible.
How do you solve matrix or grid questions in the 11+?
A matrix is a series folded into a square. Read the top row and work out the rule, confirm it against the second row, then read the columns. The missing box must satisfy both its row and its column, which gives you two independent routes to the same answer.
Why does my child find series questions so hard?
Because the changes are often tiny and more than one thing may be moving at once, so a child has to notice minute detail rather than see an obvious pattern. It is one of the hardest non-verbal types to teach, and it responds to a fixed checking order rather than to looking harder.