Number & letter sequences
35 free practice questions with explanations
PassNova has 35 free Logical & Abstract Reasoning practice questions on Number & letter sequences, each with a clear explanation. Practise them in the browser with instant feedback — 100% free, no sign-up, on any device. Updated for 2026.
Number & letter sequences: example questions & answers
35 worked examples with answers and explanations below. Practise them in the browser with instant feedback on every answer.
What comes next in the sequence: 2, 4, 6, 8, ?
- A9
- B10✓
- C11
- D12
Answer: The sequence increases by 2 each time, so after 8 comes 10.
What comes next in the sequence: 3, 6, 9, 12, ?
- A13
- B14
- C15✓
- D18
Answer: This is the 3 times table, increasing by 3 each step, so 12 + 3 = 15.
What comes next in the sequence: 1, 2, 4, 8, 16, ?
- A20
- B32✓
- C30
- D24
Answer: Each term doubles the previous one, so 16 x 2 = 32.
What comes next in the sequence: 5, 10, 15, 20, ?
- A24
- B25✓
- C30
- D35
Answer: The sequence increases by 5 each time, so 20 + 5 = 25.
What comes next in the sequence: 2, 6, 12, 20, ?
- A32
- B26
- C28
- D30✓
Answer: The differences are 4, 6, 8, then 10, so 20 + 10 = 30 (the terms are n x (n+1)).
What comes next in the sequence: 1, 4, 9, 16, 25, ?
- A30
- B36✓
- C35
- D49
Answer: These are square numbers (1, 4, 9, 16, 25), so the next is 6 squared = 36.
What comes next in the sequence: 1, 1, 2, 3, 5, 8, ?
- A10
- B12
- C11
- D13✓
Answer: This is the Fibonacci sequence where each term is the sum of the previous two, so 5 + 8 = 13.
What comes next in the sequence: 100, 90, 80, 70, ?
- A60✓
- B55
- C65
- D50
Answer: The sequence decreases by 10 each time, so 70 - 10 = 60.
What comes next in the sequence: 81, 27, 9, 3, ?
- A0
- B1✓
- C2
- D3
Answer: Each term is divided by 3, so 3 / 3 = 1.
What comes next in the sequence: 2, 3, 5, 8, 12, ?
- A15
- B16
- C17✓
- D18
Answer: The differences increase by one each time (1, 2, 3, 4, then 5), so 12 + 5 = 17.
What comes next in the sequence: 7, 14, 28, 56, ?
- A84
- B112✓
- C98
- D110
Answer: Each term is double the previous one, so 56 x 2 = 112.
What comes next in the sequence: 3, 7, 11, 15, ?
- A18
- B19✓
- C20
- D21
Answer: The sequence increases by 4 each time, so 15 + 4 = 19.
What number is missing: 4, 8, ?, 16, 20
- A10
- B11
- C12✓
- D14
Answer: This is the 4 times table, so the missing term between 8 and 16 is 12.
What comes next in the sequence: 50, 47, 44, 41, ?
- A37
- B40
- C39
- D38✓
Answer: The sequence decreases by 3 each time, so 41 - 3 = 38.
What comes next in the sequence: 1, 3, 6, 10, 15, ?
- A18
- B20
- C21✓
- D22
Answer: These are triangular numbers; the difference increases by 1 each time (5, then 6), so 15 + 6 = 21.
What comes next in the sequence: 2, 4, 8, 16, 32, ?
- A48
- B64✓
- C56
- D60
Answer: Each term doubles, so 32 x 2 = 64.
What comes next in the sequence: 90, 45, 22.5, ?
- A10.25
- B11.25✓
- C12.5
- D15
Answer: Each term is halved, so 22.5 / 2 = 11.25.
What comes next in the sequence: 1, 8, 27, 64, ?
- A100
- B121
- C125✓
- D128
Answer: These are cube numbers (1, 8, 27, 64), so the next is 5 cubed = 125.
What comes next in the sequence: 11, 13, 17, 19, 23, ?
- A25
- B27
- C29✓
- D31
Answer: These are consecutive prime numbers, and the next prime after 23 is 29.
What number is missing: 6, 12, 24, ?, 96
- A36
- B48✓
- C60
- D72
Answer: Each term doubles the previous one, so after 24 comes 48 (then 96).
What comes next in this letter sequence: A, C, E, G, ?
- AI✓
- BH
- CK
- DJ
Answer: The letters skip one each time (A, C, E, G), so the next is I.
What comes next in this letter sequence: B, D, F, H, ?
- AK
- BI
- CL
- DJ✓
Answer: The letters advance by two positions each time, so after H comes J.
What comes next in this letter sequence: A, B, D, G, K, ?
- AN
- BO
- CP✓
- DQ
Answer: The gaps between letters grow by one each time (1, 2, 3, 4, then 5), so K + 5 positions = P.
What comes next in this letter sequence: Z, X, V, T, ?
- AP
- BS
- CR✓
- DQ
Answer: The letters move back two positions each time, so after T comes R.
What comes next in this letter sequence: A, Z, B, Y, C, ?
- AD
- BW
- CE
- DX✓
Answer: The pattern alternates from the start and end of the alphabet; after C the next end-letter is X.
In a simple code A=1, B=2, C=3 and so on. What does the number 5 represent?
- AG
- BD
- CF
- DE✓
Answer: With A=1, the 5th letter of the alphabet is E.
What comes next in this letter sequence: AA, BB, CC, DD, ?
- AEE✓
- BEF
- CFF
- DDE
Answer: Each pair is a repeated letter advancing through the alphabet, so after DD comes EE.
What comes next in this letter sequence: AB, CD, EF, GH, ?
- AHI
- BHJ
- CJK
- DIJ✓
Answer: Each pair takes the next two consecutive letters, so after GH comes IJ.
What comes next in the sequence: 1, 2, 4, 7, 11, 16, ?
- A20
- B21
- C22✓
- D23
Answer: The difference increases by one each time (1, 2, 3, 4, 5, then 6), so 16 + 6 = 22.
What comes next in the sequence: 64, 32, 16, 8, ?
- A2
- B3
- C4✓
- D6
Answer: Each term is halved, so 8 / 2 = 4.
What comes next in the sequence: 10, 9, 7, 4, ?
- A0✓
- B1
- C2
- D3
Answer: The amount subtracted grows by one each time (1, 2, 3, then 4), so 4 - 4 = 0.
What comes next in the sequence: 3, 9, 27, 81, ?
- A324
- B243✓
- C216
- D162
Answer: Each term is multiplied by 3, so 81 x 3 = 243.
What comes next in the sequence: 2, 5, 10, 17, 26, ?
- A35
- B36
- C37✓
- D38
Answer: The differences are odd numbers 3, 5, 7, 9, then 11, so 26 + 11 = 37 (the terms are n squared + 1).
What comes next in the sequence: 12, 10, 8, 6, ?
- A4✓
- B2
- C3
- D5
Answer: The sequence decreases by 2 each time, so 6 - 2 = 4.
What two numbers come next: 1, 2, 4, 5, 7, 8, 10, ?, ?
- A11, 13✓
- B11, 12
- C11, 14
- D12, 13
Answer: The pattern alternates adding 1 then 2, so after 10 comes 10 + 1 = 11, then 11 + 2 = 13.