To find the common elements from given group of elements on the basis of their common properties like shapes, sizes, types, nature, colors etc is known as classification.

Types of Classification

(1) Letter/meaningless word based classification
(2) Meaningful word based classification
(3) Digit based classification (4) General knowledge based classification

Letter/Meaningless Word Based Classification

In this type of classifications questions are based on letters of English alphabet. In question many group of letters are given in which one group is different from remaining groups that different group will be our answer.

Ex. Find the odd word out of the following options.
(a) DAH    (b) IFM
(c) ROV   (d) QNT
Solution:- Correct Option (d)
In all other groups, first letters is 3 steps ahead of the second and third letters is 4 steps ahead of the first.

Ex. Find the one that does not belong to the group.
(a) JMP (b) RUX
(c) UYB (d) EHK
Solution:- Correct Option (c)
In all other groups of words, there is a gap of two letters as in the alphabet between first and second, second and third letters.

Meaningful Word Based Classification

In this type of classification questions are based on group of meaningful words in which one word is different from remaining word that different word will be our answer.

Example- (a) Slim (b) Trims (c) Greets (d) Grid (e) Fight

3. Digit Based Classification

In this type of classifications question are based on digits or numbers in which one digit or number is different from remaining numbers that different digit or number will be our answer.

Ex- Find the odd word out of the following options.
(a) 531 (b) 243
(c) 413 (d) 612
Solution:- Correct Option (c)
Except 413, the sum of the digits of each number = 9
531 = 5 + 3 + 1 = 9
243 = 2 + 4 + 3 = 9
612 = 6 + 1 + 2 = 9
But, 4 + 1 + 3 = 8 Except 413, the sum of the digits of each number = 9

General Knowledge Based Classification

In this type of classification is question are base on general knowledge.

Ex- Find the odd word out of the following options.
(a) Circle
(b) Triangle
(c) Rectangle
(d) Square
Solution:- Correct Option (a)
All others are made of straight lines.

Shortcut Approach

(1) See all the given options with a serious eye.
(2) Try to make relation of similarity among the given options. (3) Find out the one word not having the common similarity like other four options and that one word will be your answer.

Direction: Three of the four numbers/words/letters of the following question belong to the same group or class. Pick up the one does not belongs to that group.

Ex.1. Find the odd word/letters/number from the given alternatives.
(a) (108, 36)
(b) (69, 23)
(c) (42, 14)
(d) (56, 19)
Solution:- Correct Option (d)
The reason is ---
(a) (108 ÷ 3 = 36) (b) (69 ÷ 3 = 23)
(c) (42 ÷ 3 = 14) (d) Can not follow

Ex.2. Find the odd word/letters/number from the given alternatives.
(a) RQP
(b) HGF
(c) NPR
(d) DCB
Solution:- Correct Option (c)
Except (c) all are written from right to left.

Ex.3. Find the odd word/number/letters/number pair from the given alternatives.
(a) 67626
(b) 84129
(c) 32418
(d) 47632
Solution:- Correct Option (d)
Adding all the numbers of the different options gives a value which is divisible by 3. Except option (d)
(a) 6 + 7 + 6 + 2 + 6 = 27 divisible by 3
(b) 8 + 4 + 1 + 2 + 9 = 24 divisible by 3
(c) 3 + 2 + 4 + 1 + 8 = 18 divisible by 3
(d) 4 + 7 + 6 + 3 + 2 = 22 not divisible by 3

Ex.4. Find the odd word/number/letters/number pair from the given alternatives.
(a) J30T
(b) D22R
(c) H26R
(d) A28Z
Solution:- Correct Option (d)
In all other groups, number in between is the sum of positions of both letters as in the alphabet.

Ex.5. Find the odd word from the given alternatives.
(a) 853
(b) 734
(c) 532
(d) 751
Solution:- Correct Option: D
853 → 8 = (5 + 3),
734 → 7 = (3 + 4)
532 → 5 = (3 + 2),
751 → 7 = (5 + 1)
So odd number is 751 not following the pattern.