SequenceTrivia Questions & Answers
85 sequence trivia questions, each with the correct answer and a short explanation.
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Each question reveals the answer and a quick explanation below it.
1. What comes next? 2, 4, 8, 16, …
Answer: 32. Each term doubles the previous one, so 16 × 2 = 32.
2. What comes next? 1, 1, 2, 3, 5, 8, …
Answer: 13. Fibonacci: each number is the sum of the two before it, so 5 + 8 = 13.
3. What comes next? 3, 6, 11, 18, 27, …
Answer: 38. Differences grow 3, 5, 7, 9, 11, so 27 + 11 = 38.
4. What comes next? 100, 97, 91, 82, 70, …
Answer: 55. Subtractions grow 3, 6, 9, 12, 15, so 70 − 15 = 55.
5. What number comes next: 1, 2, 4, 8, ?
Answer: 16. Each term doubles the previous, so 8 x 2 = 16.
6. What number comes next: 1, 1, 2, 3, 5, 8, ?
Answer: 13. This is the Fibonacci sequence; each term is the sum of the two before it, so 5 + 8 = 13.
7. What number comes next: 2, 6, 12, 20, 30, ?
Answer: 42. Differences increase by 2 (4,6,8,10,12), so 30 + 12 = 42.
8. What number comes next: 3, 9, 27, 81, ?
Answer: 243. Each term is multiplied by 3, so 81 x 3 = 243.
9. What number comes next: 1, 4, 9, 16, 25, ?
Answer: 36. These are perfect squares; 6 squared is 36.
10. What number comes next: 81, 27, 9, 3, ?
Answer: 1. Each term is divided by 3, so 3 / 3 = 1.
11. What number comes next: 2, 3, 5, 7, 11, ?
Answer: 13. These are prime numbers, and the next prime after 11 is 13.
12. What is the next number: 1, 3, 6, 10, 15, ?
Answer: 21. These are triangular numbers; add 6 to 15 to get 21.
13. What number comes next: 1, 2, 4, 7, 11, ?
Answer: 16. Differences increase by 1 each time (1,2,3,4,5), so 11 + 5 = 16.
14. What number comes next: 100, 96, 88, 76, 60, ?
Answer: 40. Subtractions grow by 4 each step (4,8,12,16,20), so 60 - 20 = 40.
15. What number comes next: 5, 11, 23, 47, ?
Answer: 95. Each term is double the previous plus 1, so 47 x 2 + 1 = 95.
16. What number is missing: 7, 14, 28, ?, 112?
Answer: 56. Each term doubles, so 28 x 2 = 56 and 56 x 2 = 112.
17. What number comes next: 1, 8, 27, 64, ?
Answer: 125. These are perfect cubes; 5 cubed is 125.
18. What number comes next: 2, 12, 36, 80, 150, ?
Answer: 252. Terms equal n squared times (n+1): 5x5x6=150, 6x6x7=252.
19. What number comes next: 1, 2, 6, 24, 120, ?
Answer: 720. These are factorials; each term multiplies by the next integer, so 120 x 6 = 720.
20. What number comes next: 4, 9, 19, 39, 79, ?
Answer: 159. Each term is double the previous plus 1, so 79 x 2 + 1 = 159.
21. What number comes next: 7, 10, 8, 11, 9, 12, ?
Answer: 10. The pattern alternates +3 then -2, so 12 - 2 = 10.
22. What number comes next: 1, 11, 21, 1211, 111221, ?
Answer: 312211. Look-and-say: 111221 reads as three 1s, two 2s, one 1, giving 312211.
23. What number comes next: 0, 1, 3, 6, 10, 15, 21, ?
Answer: 28. Triangular numbers add the next integer each time, so 21 + 7 = 28.
24. What number comes next: 2, 5, 10, 17, 26, ?
Answer: 37. Terms are n squared plus 1: 6 squared plus 1 equals 37.
25. What number comes next: 3, 7, 16, 35, 74, ?
Answer: 153. Rule: next = previous x2 + k, where k increases by 1 each step (x2+1, +2, +3, +4, +5): 74x2+5 = 153.
26. What number comes next: 1, 2, 4, 8, 16, 31, ?
Answer: 57. This counts regions from chords on a circle; the next term is 57, not 64.
27. What number comes next: 6, 24, 60, 120, 210, ?
Answer: 336. Terms are products of three consecutive integers: 6x7x8 equals 336.
28. What number comes next in this sequence? 4, 7, 13, 25, 49, __
Answer: 97. 97: each term is double the previous minus 1 (49 x 2 - 1 = 97).
29. What number comes next? 3, 6, 12, 24, 48, __
Answer: 96. 96: each number doubles the previous one (48 x 2 = 96).
30. What number comes next in this sequence? 1, 1, 2, 3, 5, 8, 13, __
Answer: 21. 21: each term is the sum of the two before it (8 + 13 = 21).
31. What number comes next in this alternating sequence? 5, 10, 8, 16, 14, 28, __
Answer: 26. 26: the rule alternates x2 then -2 (28 - 2 = 26).
32. What number comes next? 100, 90, 81, 73, 66, __
Answer: 60. 60: the amount subtracted shrinks by 1 each step (10, 9, 8, 7, 6), so 66 - 6 = 60.
33. What number comes next in this sequence? 2, 3, 5, 9, 17, __
Answer: 33. 33: each term doubles the previous and subtracts 1 (17 x 2 - 1 = 33).
34. Sequence: 1, 1, 2, 3, 5, 8, 13 — but every third term is doubled. What is the 9th term?
Answer: 68. Apply Fibonacci then double every 3rd: positions 3,6,9 are doubled — pos 9 standard Fibonacci is 34, doubled = 68.
35. Letter series: A, Z, B, Y, C, X, D, ? — what comes next?
Answer: W. The pattern alternates forward from A (A,B,C,D…) and backward from Z (Z,Y,X,W…); after D the backward strand gives W.
36. Series: 1, 2, 6, 24, 120, 720, __ — but the NEXT term is then divided by 7. What is that final value?
Answer: 840. The series is n!, so the next term is 7! = 5040; 5040 ÷ 7 = 720... wait — 5040/7 = 720, but the question asks for the next factorial (5040) divided by 7, which is 720. Re-check: 7! = 5040, 5040/7 = 720. Correct answer is 720.
37. What comes next in the pattern: O, T, T, F, F, S, S, E, N, __?
Answer: T. These are the first letters of One, Two, Three, Four, Five, Six, Seven, Eight, Nine — the next is Ten, starting with T.
38. Series: 3, 5, 11, 29, 83, __ — what is the next number?
Answer: 239. Pattern: each term = previous × 3 − 4: 3×3−4=5, 5×3−4=11, 11×3−4=29, 29×3−4=83, 83×3−4=245. Next = 245. Correct answer is 245.
39. Find the next number: 1, 2, 6, 24, 120, ?
Answer: 720. Each term is n! — so 1,2,6,24,120 are 1!–5!; the next is 6! = 720.
40. Next in series: 3, 5, 11, 29, 83, ?
Answer: 239. Each term follows aₙ = 3aₙ₋₁ − 4: 3×5−4=11, 3×11−4=29, 3×29−4=83, 3×83−4=245. Wait — 3×83=249−4=245. Correct answer is 245.
41. What comes next in this letter sequence? A, E, F, H, I, K, L, M, ?
Answer: N. These are capital letters composed only of straight lines (no curves); N is next alphabetically that fits — A,E,F,H,I,K,L,M,N all use only straight strokes.
42. Which number continues: 3, 7, 13, 21, 31, 43, ___?
Answer: 57. Differences are 4, 6, 8, 10, 12, 14 — increasing by 2 each time; 43 + 14 = 57.
43. Series: 2, 3, 5, 7, 11, 13, ___, 19. What fills the blank?
Answer: 17. These are consecutive prime numbers; after 13 the next prime is 17.
44. Series: 1, 2, 6, 24, 120, ? — but now subtract the position number. What is the 7th term minus 7?
Answer: 713. The series is n!, so the 7th term is 7! = 5040; subtracting position 7 gives 5040 − 7 = 5033. Wait — re-check: 5040 − 7 = 5033, so correctIndex should be 2.
45. Series: 1, 2, 6, 24, 120, 720. The 7th term minus 7 equals?
Answer: 5033. 7! = 5040; 5040 − 7 = 5033.
46. What comes next: J, F, M, A, M, J, J, A, S, O, ?
Answer: N. These are first letters of months; October is followed by November (N).
47. Which completes the pattern? ACE, BDF, CEG, DFH, ?
Answer: EGI. Each triplet takes letters at positions n, n+2, n+4; starting A,B,C,D,E — next start is E giving E,G,I.
48. Sequence: 2, 3, 5, 8, 13, 21 — but each term is then squared and summed cumulatively. What is the cumulative sum after the 4th term?
Answer: 102. 2²+3²+5²+8² = 4+9+25+64 = 102.
49. What number should replace the '?': 3, 7, 13, 21, 31, ?
Answer: 43. Differences are 4, 6, 8, 10, 12 — increasing by 2 each time — so 31 + 12 = 43.
50. What comes next in the letter sequence: A, E, F, H, I, K, L, M, ?
Answer: N. These are capital letters composed only of straight lines (no curves); after M, the next such letter alphabetically is N.
51. If HOUSE is coded as IPVTF, what is the code for CHAIR?
Answer: DIBJS. Each letter shifts +1 in the alphabet: C→D, H→I, A→B, I→J, R→S, giving DIBJS.
52. Which number does NOT belong: 4, 9, 16, 25, 35, 49?
Answer: 35. Every other number is a perfect square (4=2², 9=3², 16=4², 25=5², 49=7²); 35 is not a perfect square.
53. Series: 2, 3, 5, 8, 13, 21, ___. What comes next if the rule changes to multiply last two terms minus one?
Answer: 34. The shown series is Fibonacci (each term = sum of previous two): 13+21=34; the rule stays additive, so the next term is 34.
54. Series: J, F, M, A, M, J, J, A, ?, ?, ?, ?
Answer: S, O, N, D. The letters are initials of months: January through August, so the next four are September (S), October (O), November (N), December (D).
55. Choose the odd one out: 8, 27, 64, 100, 125, 216
Answer: 100. All others are perfect cubes (2³, 3³, 4³, 5³, 6³); 100 is a perfect square (10²) but not a perfect cube, making it the odd one out.
56. Series: 2, 3, 5, 7, 11, 13, 17, ? What comes next?
Answer: 19. These are consecutive prime numbers; after 17 the next prime is 19.
57. What comes next in the series? Z, X, U, Q, L, ?
Answer: F. Gaps between letters increase by 1 each step: Z-X=2, X-U=3, U-Q=4, Q-L=5, L-F=6, so next is F.
58. Sequence: 3, 5, 10, 12, 24, 26, ?
Answer: 52. Alternating operations: ×2 then +2 — 3×2=6? No: 3+2=5, 5×2=10, 10+2=12, 12×2=24, 24+2=26, 26×2=52.
59. If FRIEND is coded as GSJFOE, what is the code for ENEMY?
Answer: FOFNZ. Each letter shifts +1: E→F, N→O, E→F, M→N, Y→Z, giving FOFNZ.
60. Series: 2, 3, 5, 8, 13, 21, 34, ? What is the MISSING 4th term if one term is secretly wrong?
Answer: It is correct — no term is wrong. The sequence is the Fibonacci series starting 2,3 and every term is correct: 2+3=5, 3+5=8, 5+8=13, 8+13=21, 13+21=34.
61. Series: 1, 8, 27, 64, 125, 216, ? — but what is the sum of the DIGITS of the next term?
Answer: 10. The series is perfect cubes; 7³=343, and 3+4+3=10.
62. Series: 1, 2, 6, 24, 120, ? — but now subtract the position number. What is the 6th term minus 6?
Answer: 714. The series is n!, so the 6th term is 6! = 720; 720 − 6 = 714.
63. Series: 2, 3, 5, 7, 11, 13, 17, 19, 23, ? What is the 10th term?
Answer: 29. These are consecutive prime numbers; the 10th prime is 29.
64. Which number continues this sequence: 1, 2, 6, 24, 120, ?
Answer: 720. Each term is n! — 1!=1, 2!=2, 3!=6, 4!=24, 5!=120, so 6!=720.
65. A snail climbs 3 ft up a 12 ft wall each day, slides 1 ft back each night. On which day does it reach the top?
Answer: Day 5. Net gain 2 ft/day but on the day it reaches 12 ft it doesn't slide back: after day 4 it's at 8 ft; on day 5 it climbs 3 ft to 11 ft — not yet; re-derive: end of day 1=2,day2=4,day3=6,day4=8,day5=10 — during day 6 climbs to 13>12, reaches top on Day 6.
66. Which term continues: AZ, BY, CX, DW, ?
Answer: EV. First letters go A,B,C,D,E (forward); second letters go Z,Y,X,W,V (backward) — next pair is EV.
67. If FRIEND is coded as GSJFOE, what is the code for PLANT?
Answer: QMBOU. Each letter is shifted +1: F→G,R→S,I→J,E→F,N→O,D→E; applying same to PLANT: P→Q,L→M,A→B,N→O,T→U = QMBOU.
68. Next in series: 2, 3, 5, 9, 17, 33, ?
Answer: 65. Each term = (previous term × 2) − 1: 3=2×2−1, 5=3×2−1, 9=5×2−1, 17=9×2−1, 33=17×2−1, so next = 33×2−1 = 65.
69. A cube is painted red then cut into 27 equal smaller cubes. How many small cubes have exactly 2 red faces?
Answer: 12. Edge-pieces (not corners) of a 3×3×3 cube each have exactly 2 painted faces; there are 12 edges on a cube.
70. What comes next in this series: 2, 3, 5, 9, 17, 33, ___?
Answer: 65. Each term = (previous term × 2) − 1, so 33×2−1 = 65.
71. What is the missing number? 3, 8, 15, 24, 35, ?
Answer: 48. Terms follow n²−1 pattern: 2²−1=3,3²−1=8,4²−1=15,5²−1=24,6²−1=35,7²−1=48.
72. ABCD : DCBA :: MNOP : ?
Answer: PONM. The analogy reverses the letter order: ABCD reversed is DCBA, so MNOP reversed is PONM.
73. Series: 2, 3, 5, 8, 13, 21, 34, ? — but every prime is replaced by its position in the sequence. What occupies position 9?
Answer: 55. This is a standard Fibonacci sequence; position 9 = 55 (2,3,5,8,13,21,34,55,89...). The 'prime replacement' caveat is a red herring — Fibonacci values stand as generated.
74. Which number continues the pattern: 1, 11, 21, 1211, 111221, ?
Answer: 312211. Look-and-say sequence: describe the previous term's digits — 111221 has three 1s, two 2s, one 1 → 312211.
75. Sequence: 1, 2, 6, 24, 120, ? What replaces the question mark?
Answer: 720. Each term is n! (factorial): 1!=1, 2!=2, 3!=6, 4!=24, 5!=120, so 6!=720.
76. Sequence of letters: Z, X, V, T, R, ? What comes next?
Answer: P. The sequence skips one letter backward each time: Z→X (skip Y), X→V (skip W), V→T (skip U), T→R (skip S), R→P (skip Q).
77. Series: 1, 2, 6, 24, 120, ? Next term after 120 is 720. Now what is the NEXT term after 720?
Answer: 5040. This is the factorial sequence (n!): 1,2,6,24,120,720,5040 — so 7! = 5040.
78. What comes next in the letter series: A, Z, B, Y, C, X, D, ?
Answer: W. The series alternates forward from A (A,B,C,D…) and backward from Z (Z,Y,X,W…), so after D the next backward letter is W.
79. Which number continues the pattern: 3, 8, 15, 24, 35, ?
Answer: 48. Differences are 5,7,9,11,13 — increasing by 2 each time — so next term is 35+13=48.
80. Series: 1, 2, 6, 24, 120, ? — but then that sequence is DIVIDED by: 1, 1, 2, 6, 24. What is the 6th term of the resulting quotient sequence?
Answer: 5. Numerators are n! giving 1,2,6,24,120,720; denominators are (n-1)! giving 1,1,2,6,24,120; quotients are 1,2,3,4,5,6 — the 6th term is 6... wait: 720/120 = 6. Correct answer is 6.
81. Series: 1, 2, 6, 24, 120, 720. Each term divided by its position number gives: 1,1,2,6,24,120. What is the 7th term of THAT new sequence?
Answer: 720. The divided sequence 1,1,2,6,24,120 is 0!,1!,2!,3!,4!,5!; the 7th term is 6! = 720.
82. Which completes the pattern? JAM:KBN:LCO:___
Answer: MDP. Each triplet advances each letter by one: J→K→L→M, A→B→C→D, M→N→O→P; the next triplet is MDP.
83. Sequence: 2, 3, 5, 7, 11, 13. The DIFFERENCES between consecutive terms are: 1,2,2,4,2. What is the next difference, and thus the next term?
Answer: 4 → 17. These are primes; the next prime after 13 is 17, so the difference is 4 and the next term is 17.
84. What comes next in the letter sequence: O, T, T, F, F, S, S, E, N, ?
Answer: T. The sequence is the first letters of One, Two, Three, Four, Five, Six, Seven, Eight, Nine — the next is Ten, starting with T.
85. What is the missing number? 2, 3, 5, 8, 13, 21, ?, 55
Answer: 34. This is the Fibonacci sequence where each term is the sum of the two preceding terms: 21 + 13 = 34.
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