Round two!
Here are 10 fresh missing-number sequence puzzles.
Choose from the options, then click Show answer to reveal the explanation.
Worked Example
Sequence: 3, 6, 10, 15, ?
Options: A) 19 B) 20 C) 21 D) 22
Show answer
Differences are +3, +4, +5… so the next difference is +6.
15 + 6 = 21 → C) 21.
Puzzle 1
Sequence: 6, 11, 17, 24, ?
Options: A) 30 B) 31 C) 32 D) 33
Show answer
Differences: +5, +6, +7 → next +8.
24 + 8 = 32 → C.
Puzzle 2
Sequence: 2, 6, 18, 54, ?
Options: A) 108 B) 162 C) 216 D) 324
Show answer
Geometric progression ×3 each step → 54 × 3 = 162 → B.
Puzzle 3
Sequence: 1, 4, 10, 20, 35, ?
Options: A) 49 B) 52 C) 55 D) 56
Show answer
Add triangular numbers: +3, +6, +10, +15 → next +21.
35 + 21 = 56 → D.
Puzzle 4
Sequence: 9, 7, 14, 12, 24, 22, ?
Options: A) 34 B) 37 C) 39 D) 41
Show answer
Pattern alternates: −2, then “add +7, +12, +17…” (the addends grow by +5).
22 + 17 = 39 → C.
Puzzle 5
Sequence: 2, 3, 5, 9, 17, ?
Options: A) 26 B) 31 C) 33 D) 35
Show answer
Differences double: +1, +2, +4, +8 → next +16.
17 + 16 = 33 → C.
Puzzle 6
Sequence: 64, 32, 16, 8, ?, 2
Options: A) 3 B) 4 C) 5 D) 6
Show answer
Halving each time: 64 → 32 → 16 → 8 → 4 → 2.
Missing term is 4 → B.
Puzzle 7
Sequence: 3, 9, 12, 36, 39, 117, ?
Options: A) 118 B) 120 C) 351 D) 360
Show answer
Alternate “×3, then +3”: 3×3=9; +3=12; ×3=36; +3=39; ×3=117; +3=120.
Answer 120 → B.
Puzzle 8
Sequence: 1, 2, 4, 7, 11, 16, ?
Options: A) 20 B) 21 C) 22 D) 23
Show answer
Differences grow +1, +2, +3, +4, +5 → next +6.
16 + 6 = 22 → C.
Puzzle 9
Sequence: 5, 12, 26, 54, 110, ?
Options: A) 210 B) 220 C) 222 D) 224
Show answer
Rule: “×2 + 2” each step.
5→12 (×2+2), 12→26, 26→54, 54→110, next 110×2+2 = 222 → C.
Puzzle 10
Sequence: 7, 10, 16, 28, 52, ?
Options: A) 84 B) 96 C) 100 D) 104
Show answer
Differences double: +3, +6, +12, +24 → next +48.
52 + 48 = 100 → C.