Patwari Exam · Reasoning
Classification: Odd One Out
This note explains the method for spotting the option that doesn't fit in classification (Odd One Out) questions.
- Reasoning & Numerical Ability
- 5 min read
Verified 6 October 2026
Key Formulas & Methods
- Classification method
- Method: find a common feature shared by all the options; the one that doesn't fit is the answer.
- Animal classification example
- Example (animals): Dog, Cat, Horse, Eagle → the first three are mammals, Eagle is a bird → answer: Eagle.
- Number classification example
- Example (numbers): 4, 9, 16, 23, 25 → 4=2², 9=3², 16=4², 25=5² but 23 is not a perfect square → answer: 23.
- Odd-letter classification
- Odd letters: BCE, ACE, BDF, AEG → BCE=2+3+5, ACE=1+3+5, BDF=2+4+6 (consecutive even), AEG=1+5+7 → answer: AEG.
- Property-based classification
- Property-based: Red, Blue, Green, Sweet → the first three are colors, Sweet is food → answer: Sweet.
- Exam tip
- Exam tip: try more than one basis (color, shape, category, mathematical property).
Frequently Asked Questions
What is the method for finding the Odd One Out?+
Find a common feature shared by all the options; whichever option doesn't fit that common feature is the answer.
How do you spot the odd one in number classification?+
For example, in 4, 9, 16, 23, 25 — 4, 9, 16, 25 are perfect squares (2², 3², 4², 5²) but 23 is not a perfect square, so 23 is the odd one.
Why should you try more than one basis?+
Sometimes the common feature is based on color, shape, category, or a mathematical property, so you should try more than one basis to catch the right pattern.