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Classification

Practice MCQs

Classification questions test your ability to group similar items and identify the one that does not belong.

Reasoning Ability Classification Competitive Exams

Classification is an important reasoning ability topic where you are asked to identify the item that does not belong to a given group. These questions test your ability to observe similarities, compare features, and find the odd one out.

What is Classification?

Classification means grouping items based on a common property. In reasoning questions, four or five options are given, and most of them share a common feature. One option does not follow the same rule. That option is called the odd one out.

The items may be words, letters, numbers, objects, animals, places, professions, or mixed patterns. Your task is to identify the common relationship among the majority of items and then eliminate the one that is different.

Quick idea: First find what is common among most options. Then check which option does not share that property.
Group Common Feature Odd One Out
Apple, Mango, Banana, Carrot First three are fruits Carrot
Dog, Cat, Lion, Sparrow First three are mammals Sparrow
2, 4, 6, 9 First three are even numbers 9
A, E, I, B First three are vowels B

“Classification questions are solved by finding the rule that connects most of the options.”

Reasoning Tip
Key points
  • Find the common feature first.
  • Compare all options carefully.
  • Do not select based on appearance alone.
  • Check category, use, property, spelling, or number pattern.
  • One option usually breaks the common rule.
  • Sometimes more than one feature may be possible.
odd one out grouping category logic

Common Types of Classification Questions

Classification questions can be based on words, numbers, letters, meanings, categories, or general knowledge. The following types are commonly asked in competitive exams.

Word Classification

Find the word that does not belong to the group.

  • Rose, Lotus, Lily, Mango
  • First three are flowers
  • Mango is fruit
  • Odd one: Mango
Number Classification

Find the number that differs from others.

  • 4, 9, 16, 20
  • 4, 9, 16 are squares
  • 20 is not a square
  • Odd one: 20
Letter Classification

Find the letter or group that breaks the pattern.

  • A, E, I, K
  • A, E, I are vowels
  • K is consonant
  • Odd one: K
Pair Classification

Find the pair that has a different relationship.

  • Pen-Write
  • Knife-Cut
  • Key-Open
  • Book-Table
Rule: The odd one out must be selected based on a clear logical difference, not just personal preference or familiarity.
Classification Pattern Bank
Category Based
Apple, Mango, Banana → Fruits
Rose, Lily, Lotus → Flowers
Cow, Goat, Dog → Animals
Property Based
Even numbers
Odd numbers
Prime numbers
Square numbers
Function Based
Pen → Write
Knife → Cut
Key → Open
Brush → Paint
Letter Based
Vowels and consonants
Alphabet position
Forward/backward movement
Fixed gap pattern

Tip: Always ask: “What property do most options share?” The answer to this question reveals the odd one out.

Classification reasoning concept
Classification questions test your ability to group similar items and identify the one that does not belong.

Step-by-Step Solving Method

Step Action Example
Step 1 Read all options carefully. Apple, Mango, Banana, Carrot
Step 2 Find a common feature among most options. Apple, Mango, and Banana are fruits.
Step 3 Check which option does not share the common feature. Carrot is not a fruit; it is a vegetable.
Step 4 Verify the rule with all options. Only Carrot breaks the fruit category rule.
Step 5 Select the odd one out. Answer: Carrot
Important: In difficult questions, more than one relationship may seem possible. Choose the strongest and most consistent rule.

Solved Examples

Question Method Answer
Find the odd one out: Rose, Lotus, Lily, Apple Rose, Lotus, and Lily are flowers.
Apple is a fruit. 		Apple
Find the odd one out: Dog, Cat, Cow, Crow Dog, Cat, and Cow are mammals.
Crow is a bird. 		Crow
Find the odd one out: 4, 9, 16, 20 4 = 2², 9 = 3², 16 = 4².
20 is not a perfect square. 		20
Find the odd one out: 2, 3, 5, 9 2, 3, and 5 are prime numbers.
9 is not a prime number. 		9
Find the odd one out: A, E, I, P A, E, and I are vowels.
P is a consonant. 		P
Find the odd one out: AB, CD, EF, GH, IJ, KL, MN, OP, QR, ST, VX Most pairs are consecutive letters.
V and X are not consecutive because W comes between them. 		VX
Find the odd one out: Pen-Write, Knife-Cut, Key-Open, Book-Read Each pair shows object and function.
All follow the same relationship. 		No odd one
Find the odd one out: Triangle, Square, Rectangle, Circle Triangle, square, and rectangle have straight sides.
Circle has no straight side. 		Circle

Note: In some questions, the odd one may be based on meaning, spelling, shape, number property, or relationship between pairs.

Common Traps and Shortcuts

Common Traps
  • Selecting an option without finding the common rule.
  • Choosing based only on word familiarity.
  • Ignoring number properties such as prime, square, or cube.
  • Confusing category and function-based classification.
  • Not checking spelling or alphabet position patterns.
  • Missing hidden relationship in pair classification.
Useful Shortcuts
  • Find the rule that applies to most options.
  • Check category, property, function, and relationship.
  • For numbers, test even, odd, prime, square, cube, and divisibility.
  • For letters, check vowels, consonants, positions, and gaps.
  • For words, check meaning, usage, group, and spelling.
  • Verify that only one option breaks the rule.
Exam approach: Identify whether the question is based on word category, number property, letter pattern, function relation, shape, or general knowledge grouping.

Practice

A) Multiple Choice Questions
  1. Find the odd one out: Apple, Mango, Banana, Potato
    Apple Mango Banana Potato
  2. Find the odd one out: 3, 5, 7, 9
    3 5 7 9
  3. Find the odd one out: A, E, I, R
    A E I R
  4. Find the odd one out: 8, 27, 64, 100
    8 27 64 100
  5. Find the odd one out: Pen-Write, Knife-Cut, Key-Open, Chair-Sit
    Pen-Write Knife-Cut Key-Open Chair-Sit
B) Solve the Higher-Order Problems
  1. Find the odd one out: 16, 25, 36, 49, 60 (Hint: Check perfect squares.)
  2. Find the odd one out: AB, CD, EF, GH, IK (Hint: Check consecutive letters.)
  3. Find the odd one out: Doctor-Hospital, Teacher-School, Farmer-Field, Pen-Write (Hint: Check person and workplace relationship.)
  4. Find the odd one out: January, March, May, June (Hint: Check number of days in the month.)
  5. Find the odd one out: Triangle, Square, Rectangle, Cube (Hint: Check 2D and 3D shapes.)
C) Match the Group with the Correct Classification Rule
Group Correct Rule / Meaning
Apple, Mango, Banana Fruits
Rose, Lotus, Lily Flowers
2, 3, 5, 7 Prime numbers
A, E, I, O, U Vowels
4, 9, 16, 25 Perfect squares
Pen-Write, Knife-Cut, Key-Open Object and function relation
Reasoning Reminder

Classification questions are solved by identifying the common feature among most options and selecting the item that does not follow the same rule. The common feature may be based on category, meaning, function, number property, letter pattern, shape, or general knowledge.

Task: Create five classification questions using word groups, number properties, letter patterns, object-function pairs, and shape-based groups.

Show Suggested Answers
Multiple Choice
  1. Potato
    Apple, Mango, and Banana are fruits. Potato is a vegetable.
  2. 9
    3, 5, and 7 are prime numbers. 9 is not a prime number.
  3. R
    A, E, and I are vowels. R is a consonant.
  4. 100
    8 = 2³, 27 = 3³, 64 = 4³. 100 is not a perfect cube.
  5. Chair-Sit
    Pen-Write, Knife-Cut, and Key-Open show object and direct function. Chair-Sit is different because a chair is used for sitting, but “sit” is not an action performed by the chair itself.
Higher-Order Problems
  1. 16, 25, 36, 49 are perfect squares.
    60 is not a perfect square.
    Answer = 60.
  2. AB, CD, EF, GH are consecutive letter pairs.
    IK is not consecutive because J comes between I and K.
    Answer = IK.
  3. Doctor-Hospital, Teacher-School, and Farmer-Field show person and workplace.
    Pen-Write shows object and function.
    Answer = Pen-Write.
  4. January, March, and May have 31 days.
    June has 30 days.
    Answer = June.
  5. Triangle, Square, and Rectangle are 2D shapes.
    Cube is a 3D shape.
    Answer = Cube.
Concept Matching
  1. Apple, Mango, Banana → Fruits
  2. Rose, Lotus, Lily → Flowers
  3. 2, 3, 5, 7 → Prime numbers
  4. A, E, I, O, U → Vowels
  5. 4, 9, 16, 25 → Perfect squares
  6. Pen-Write, Knife-Cut, Key-Open → Object and function relation
Clue Explanation

Classification questions depend on finding the strongest common rule. Once the common rule is clear, the odd one out can be identified quickly and accurately.

Exam tips
  • Find the common rule before selecting the answer.
  • Check meaning, category, function, and property.
  • For numbers, test prime, square, cube, odd, and even.
  • For letters, check vowels, consonants, and alphabet gaps.
  • For pairs, identify the relationship between the two words.
  • Verify that only one option breaks the rule.
Practice MCQs