Number Series Test Practice
A number series test shows a row of numbers that follow a hidden rule and asks which number comes next. It measures how fast you can work out the rule and apply it. A short list of rules covers nearly every question: fixed adding or multiplying, growing gaps, two series woven together, and terms built from earlier ones.
Number series tests give you a row of whole numbers with the next one missing and ask you to choose it from a few options. Employers and training providers use them as a quick check of numerical pattern recognition, usually inside a wider aptitude or numerical reasoning round. The numbers are small on purpose. What is being tested is whether you can see the rule, not whether you can do hard sums.
The rules come from a short list. Most series add or multiply by a fixed amount. The next group has gaps that grow, such as a gap of one, then two, then three. Others weave two separate series into one row, or build each number from the ones before it, as in the sum of the previous two. A routine that checks these in a fixed order beats staring at the row and hoping the rule jumps out.
Below are original sample questions, one for each main kind of rule. Each shows the four options, the answer, and the check that proves it: a rule only counts if it reproduces every number shown, not just the last two. The JobCannon number series test follows the same pattern if you want a scored attempt after reading.
The format at a glance
- Format
- A row of whole numbers with the next term missing, answered by choosing one of several options
- Time limit
- Set by each employer or publisher, so practise against a fixed per-question budget instead of a remembered figure
- Question types
- Steady steps, growing gaps, two series woven into one row, and terms built from earlier terms
- Scoring
- Each answer is right or wrong; some tests also penalise wrong answers, so read the instructions you are given before you guess
- Who uses it
- Employers and training providers that screen for numerical pattern recognition, often inside a wider aptitude battery
What it measures
Rule finding, not arithmetic
A number series question asks you to infer a rule from a few examples and apply it once more. The sums involved are light. What separates a quick answer from a slow one is how soon you ask the right question about the row: is the gap steady, is the ratio steady, or are two series sharing the row.
The rule catalogue
Nearly every series comes from a short list: adding or subtracting a fixed amount, multiplying or dividing by a fixed factor, gaps that grow by a fixed step or double, squares and cubes, two interleaved series, a term built from the previous two, and a chain of two operations repeated. Learning the list pays off faster than doing questions at random.
Why every number must be checked
A rule that fits the first three numbers can fail on the fourth. The row 1, 2, 4 could go on to 8 by doubling or to 7 by growing gaps, and only a further term settles it. Test your rule against every number shown before you commit, because the option you want and a trap option often differ by one slip.
Speed and the cost of a stall
Most number series tests run against a clock, so a series that does not yield in a reasonable time costs the ones you would have solved later. Practice therefore needs a fixed per-question budget and the habit of parking a stubborn row, which is a different skill from solving it eventually.
Practice questions with worked answers
Written by us to mirror the published format. Work each one out before you read the explanation — the method is the part that transfers, the answer is not.
- Q1Steady steps: add
What number comes next: 6, 15, 24, 33, 42, ?
- 51
- 52
- 54
- 57
Correct answer
51. The gap between neighbours is 9 every time (15 - 6, 24 - 15, 33 - 24, 42 - 33), so the rule is add 9. Then 42 + 9 = 51. The other options come from slips: a gap of 10, or a gap that grows, neither of which fits the numbers shown.
- Q2Steady steps: multiply
What number comes next: 3, 12, 48, 192, ?
- 336
- 384
- 576
- 768
Correct answer
768. The gaps (9, 36, 144) are not steady, so check the ratios: 12 / 3, 48 / 12 and 192 / 48 are all 4. The rule is multiply by 4, and 192 x 4 = 768. The option 336 repeats the last gap of 144, 384 doubles and 576 triples, none of which matches the ratio.
- Q3Growing steps
What number comes next: 4, 5, 7, 10, 14, 19, ?
- 24
- 25
- 26
- 27
Correct answer
25. Write the gaps: 1, 2, 3, 4, 5. They are not equal, but they rise by one each time, so the next gap is 6 and 19 + 6 = 25. Repeating the last gap of 5 gives 24, and growing the gap too fast gives 26 or 27.
- Q4Growing steps: cubes
What number comes next: 2, 9, 28, 65, 126, 217, ?
- 308
- 342
- 343
- 344
Correct answer
344. Each number is a cube plus one: 1 + 1, 8 + 1, 27 + 1, 64 + 1, 125 + 1, 216 + 1. The next cube is 7 x 7 x 7 = 343, so the term is 344. The option 343 forgets the plus one, and 308 comes from repeating the last gap of 91.
- Q5Two series
What number comes next: 5, 40, 8, 35, 11, 30, 14, 25, ?
- 15
- 17
- 20
- 22
Correct answer
17. The row jumps up and down, so split it into odd and even places. Places 1, 3, 5, 7 give 5, 8, 11, 14 (add 3); places 2, 4, 6, 8 give 40, 35, 30, 25 (subtract 5). The ninth term is in the first list, so it is 14 + 3 = 17. The option 20 carries on the other series by mistake.
- Q6Chained rules: sum of two
What number comes next: 4, 5, 9, 14, 23, 37, ?
- 51
- 59
- 60
- 61
Correct answer
60. No steady gap or ratio appears, but each number is the sum of the two before it: 4 + 5 = 9, 5 + 9 = 14, 9 + 14 = 23, 14 + 23 = 37. So the next is 23 + 37 = 60. The option 51 repeats the last gap of 14 and 59 and 61 are arithmetic slips.
- Q7Chained rules: two operations
What number comes next: 5, 7, 11, 19, 35, ?
- 67
- 69
- 70
- 71
Correct answer
67. Double and take away 3: 5 x 2 - 3 = 7, 7 x 2 - 3 = 11, 11 x 2 - 3 = 19, 19 x 2 - 3 = 35, so 35 x 2 - 3 = 67. The gaps (2, 4, 8, 16) also double, which gives the same answer. Options 69, 70 and 71 come from forgetting or changing the minus 3.
- Q8Chained rules: alternating operations
What number comes next: 4, 12, 9, 27, 24, 72, ?
- 63
- 66
- 69
- 75
Correct answer
69. The rule alternates two steps: multiply by 3, then subtract 3. 4 x 3 = 12, 12 - 3 = 9, 9 x 3 = 27, 27 - 3 = 24, 24 x 3 = 72, so the step after 72 is subtract 3, giving 69. The option 75 adds instead of subtracting.
How scores are read
Seeing the rule at a glance
You name the rule from the first three or four numbers and use the options only to confirm it. That pace suits a timed format, and the habit that produces it is writing the gaps and ratios without thinking about it.
Finding it with the routine
You get there by writing the gaps, then the ratios, then trying a split into two lists. That is a sound method and fine for untimed practice. Under a clock the gain comes from running the same steps faster, not from learning new ones.
Finding it only when told the kind
You solve a series once someone has said whether it is steady, growing or two interleaved, but not before. The fix is to make the sorting step explicit: decide which of the main kinds a row is before trying to solve it.
Pass marks vary
Employers and publishers set their own bar for the same kind of test and rarely publish it. Treat any band above as a description of your method, not a prediction of an outcome.
Try the free JobCannon Number Series Test
Sit a full-length version under the clock and get a scored report you keep, so the next practice session works on the gap rather than on everything at once.
Start the free test24 questions · 9 min · No signup to start
How to prepare
Write the gaps first, every time
Put the difference between each pair of neighbours under the row before you think about anything else. Equal gaps mean a steady step, gaps that rise or fall by a steady amount mean you take the gaps of the gaps, and gaps that double or triple point to a ratio.
Check ratios when the numbers grow fast
If each number is at least double the one before, the gaps are unlikely to be clean. Divide each number by the one before it. A steady ratio means a multiplier, and a ratio that itself changes means a growing multiplier.
Split a zigzag row in two
If the numbers rise and fall in turn, or one half looks steady and the other does not, list the odd places and the even places separately and solve each list on its own. Then work out which list the missing place belongs to before you answer.
Test the rule on every number
Once you have a rule, run it from the first number to the last shown. A rule that fits three terms and fails the fourth was a coincidence. Doing this check takes seconds and removes the most common way to lose a point on a row you understood.
Know the lists by heart
Squares up to 15, cubes up to 10 and powers of 2 up to 1024 turn a hard-looking row into a simple one, because you recognise 125 or 144 at a glance. A few minutes spent on these lists saves more time than the same minutes spent on extra questions.
Review misses by kind of rule
After a practice set, sort your wrong answers by the kind of rule they used, not by their position in the set. If most misses are two interleaved series, practise the split. If they are chained rules, practise saying the rule in one sentence before choosing.
A number series test shows a row of whole numbers that follow a hidden rule, with the next number missing, and asks you to choose it from several options. It checks whether you can infer a rule from a few examples and apply it again. The sums are simple, and the skill is seeing the rule.
Write the gaps between neighbouring numbers. If they are equal, the rule is addition. If not, check whether they follow their own pattern, then check the ratios. If the numbers jump up and down, split the row into odd and even places and solve each list separately. Test the rule on every number.
The common ones are adding or subtracting a fixed amount, multiplying or dividing by a fixed factor, gaps that grow by a fixed step, square and cube numbers, two series woven into one row, a term built from the previous two, and two operations repeated in turn. The samples above cover each.
Work through the samples above, covering the answer and the explanation until you have a rule of your own, then compare. Give yourself a fixed time per question. When a miss comes from one kind of rule, write a few series of that kind yourself and solve them cold the next day.
No. A number series test asks for the next term of a row. A numerical reasoning test usually covers percentages, ratios, and tables or charts, and some include sequences as one section. Number series is the narrower test, and it trains the rule-finding habit that the wider one uses.
It depends on the employer or publisher, and the limit is set by them. A sensible way to practise is to pick a fixed budget per question, stop when it runs out, mark your best guess and move on. The habit of parking a stubborn series matters as much as raw speed.
Most people find the rules come from a short list, so learning the list and a fixed routine makes rules faster to spot. How much it helps varies from person to person. Review your misses by kind of rule, because that shows where the next gain is, instead of just doing more questions.
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