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
12 worked examples with answers and explanations below. Practise all 35 Number & letter sequences questions free 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, ?
- A24
- B30
- C32✓
- D20
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, ?
- A28
- B30✓
- C32
- D26
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, ?
- A11
- B12
- C13✓
- D10
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, ?
- A65
- B60✓
- C55
- 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
- B98
- C112✓
- 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.