Odd Man Out and Series— Concepts, Formulas & Shortcuts
- Run the checklist: primes → perfect squares → perfect cubes → common multiples → odd/even.
- Perfect squares to recognise: 4, 9, 16, 25, 36, 49, 64, 81, 100, 121, 144.
- Perfect cubes to recognise: 8, 27, 64, 125, 216, 343, 512.
- If most terms share a divisor, the odd one is the term that does not.
- For letter sets, check alphabet positions and vowel/consonant patterns.
- The rule must fit ALL the other terms — if it fits only some, you have the wrong rule.
Odd Man Out and Series Practice Questions with Answers
Attempt each question first, then open the explanation. All 20 questions below are free to read and require no signup.
Q1.Find the odd one out: 2, 3, 5, 7, 9, 11
Easy- A3
- B5
- C9
- D11
Odd Man Out and Series question 1 of 20+Show Answer & Explanation
Answer: C. 9
Explanation: All are prime except 9, which is 3 × 3.
Q2.Find the odd one out: 4, 9, 16, 23, 25
Easy- A9
- B16
- C23
- D25
Odd Man Out and Series question 2 of 20+Show Answer & Explanation
Answer: C. 23
Explanation: All are perfect squares except 23.
Q3.Find the odd one out: 8, 27, 64, 100, 125
Moderate- A27
- B64
- C100
- D125
Odd Man Out and Series question 3 of 20+Show Answer & Explanation
Answer: C. 100
Explanation: All are perfect cubes (2³, 3³, 4³, 5³) except 100, which is a perfect square.
Q4.Find the odd one out: 41, 43, 47, 53, 55
Easy- A43
- B47
- C53
- D55
Odd Man Out and Series question 4 of 20+Show Answer & Explanation
Answer: D. 55
Explanation: All are prime except 55 = 5 × 11.
Q5.Find the odd one out: 10, 25, 45, 54, 60
Easy- A25
- B45
- C54
- D60
Odd Man Out and Series question 5 of 20+Show Answer & Explanation
Answer: C. 54
Explanation: All are multiples of 5 except 54.
Q6.Find the odd one out: 3, 5, 11, 14, 17, 21
Easy- A5
- B11
- C14
- D21
Odd Man Out and Series question 6 of 20+Show Answer & Explanation
Answer: C. 14
Explanation: Every term is odd except 14.
Q7.Find the odd one out: 16, 25, 36, 48, 64
Easy- A25
- B36
- C48
- D64
Odd Man Out and Series question 7 of 20+Show Answer & Explanation
Answer: C. 48
Explanation: All are perfect squares except 48.
Q8.Find the odd one out: 3, 6, 9, 13, 15
Easy- A6
- B9
- C13
- D15
Odd Man Out and Series question 8 of 20+Show Answer & Explanation
Answer: C. 13
Explanation: All are multiples of 3 except 13.
Q9.Find the odd one out: 1, 8, 27, 49, 125
Moderate- A8
- B27
- C49
- D125
Odd Man Out and Series question 9 of 20+Show Answer & Explanation
Answer: C. 49
Explanation: All are perfect cubes except 49, which is a perfect square.
Q10.Find the odd one out: 12, 24, 34, 48, 60
Moderate- A24
- B34
- C48
- D60
Odd Man Out and Series question 10 of 20+Show Answer & Explanation
Answer: B. 34
Explanation: All are multiples of 12 except 34.
Q11.Find the odd one out: 22, 33, 44, 55, 67
Easy- A33
- B44
- C55
- D67
Odd Man Out and Series question 11 of 20+Show Answer & Explanation
Answer: D. 67
Explanation: All are multiples of 11 except 67.
Q12.Find the odd one out: 2, 5, 10, 17, 26, 38
Difficult- A10
- B17
- C26
- D38
Odd Man Out and Series question 12 of 20+Show Answer & Explanation
Answer: D. 38
Explanation: The pattern is n² + 1 for n = 1 to 6: 2, 5, 10, 17, 26, 37 — so 38 breaks it.
Q13.Find the odd one out: 121, 144, 169, 200, 225
Easy- A144
- B169
- C200
- D225
Odd Man Out and Series question 13 of 20+Show Answer & Explanation
Answer: C. 200
Explanation: All are perfect squares (11², 12², 13², 15²) except 200.
Q14.Find the odd one out: 5, 10, 15, 22, 25
Easy- A10
- B15
- C22
- D25
Odd Man Out and Series question 14 of 20+Show Answer & Explanation
Answer: C. 22
Explanation: All are multiples of 5 except 22.
Q15.Find the odd one out: 2, 4, 6, 9, 10
Easy- A4
- B6
- C9
- D10
Odd Man Out and Series question 15 of 20+Show Answer & Explanation
Answer: C. 9
Explanation: All are even except 9.
Q16.Find the odd one out: 11, 13, 17, 19, 21
Easy- A13
- B17
- C19
- D21
Odd Man Out and Series question 16 of 20+Show Answer & Explanation
Answer: D. 21
Explanation: All are prime except 21 = 3 × 7.
Q17.Find the odd one out: 64, 81, 100, 120, 144
Easy- A81
- B100
- C120
- D144
Odd Man Out and Series question 17 of 20+Show Answer & Explanation
Answer: C. 120
Explanation: All are perfect squares except 120.
Q18.Find the odd one out: 1, 8, 27, 64, 100
Moderate- A8
- B27
- C64
- D100
Odd Man Out and Series question 18 of 20+Show Answer & Explanation
Answer: D. 100
Explanation: All are perfect cubes except 100.
Q19.Find the odd one out: 14, 28, 42, 55, 70
Moderate- A28
- B42
- C55
- D70
Odd Man Out and Series question 19 of 20+Show Answer & Explanation
Answer: C. 55
Explanation: All are multiples of 14 except 55.
Q20.Find the odd one out: 3, 7, 15, 31, 62
Difficult- A7
- B15
- C31
- D62
Odd Man Out and Series question 20 of 20+Show Answer & Explanation
Answer: D. 62
Explanation: The rule is ×2 + 1: 3, 7, 15, 31, 63 — so 62 breaks the pattern.
Odd Man Out and Series — Frequently Asked Questions
What should I check first in an odd-man-out question?+
Whether the numbers are primes, then perfect squares, then perfect cubes, then multiples of a common number. That sequence resolves the large majority of exam sets in under fifteen seconds.
What if two different rules seem to work?+
Choose the rule that excludes exactly one term. If two candidates remain, prefer the more specific property — being a perfect cube is more specific than being even.
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