Verbal Reasoning Number Series
A Number Series question shows a row of numbers that follow a hidden rule; you work out the rule linking them, then continue it. The rule is almost never "just add the same thing" — the exam hides it in the gaps between the numbers, or in two little series woven together.
💡 Worked example
Find the number that continues the series:
5 8 13 16 21 [?]
How to answer
Common things to look for
A number series hides one of these rules — check each in turn:
- A steady step — the same amount is added or subtracted each time (+3, +3, +3…). Always the first thing to test.
- A changing step — the step alternates (+3, +5, +3, +5) or grows by one each time (+4, +5, +6…).
- Two series woven together — the 1st, 3rd, 5th numbers follow one rule and the 2nd, 4th, 6th follow another; split them apart and continue the one the [?] belongs to.
- Multiply then adjust — each term is ×2 then +1, or ×3 then −2, when plain adding won't fit.
- Doubling or halving — the numbers double (3, 6, 12, 24…) or halve (64, 32, 16…).
Watch for these traps
- Assuming one fixed step. Many exam series do not add the same number each time — always check several gaps before you decide.
- Missing two woven series. If the numbers jump up and down, split them into odd and even positions — each follows its own rule, and the [?] only cares about its own half.
- Stopping at the first rule that half-fits. Test your rule on every gap, not just the first two, before you trust it.
Try these yourself
Now have a go yourself — tap the number that comes next.
✏️ Question 1
Find the number that continues the series:
10 14 19 25 32 [?]
The answer is 40
the differences grow by one: +4, +5, +6, +7, then +8, so 32 + 8 = 40.
✏️ Question 2
Find the number that continues the series:
4 30 7 25 10 20 13 [?]
The answer is 15
two series are woven together: the odd positions 4, 7, 10, 13 go up +3, and the even positions 30, 25, 20 go down −5, so the next number is 20 − 5 = 15.
✏️ Question 3
Find the number that continues the series:
1 5 13 29 [?]
The answer is 61
each number is ×2 then +3: 1→5→13→29→61.
Related
- The complete 11+ question-type guide
- VR: Letter Series — the same "find the rule, continue it" trick with letter pairs
- VR: Letter Analogies — apply a letter shift to a new pair
- VR: Complete the Sum — make both sides of an equals sign match
All example questions come from the Brainblox question bank — practise this question type inside 15 arcade games, timed mock exams and focused practice. Brainblox is an independent app: not affiliated with, endorsed by or licensed by any exam board, school or assessment publisher, and it contains no past papers.