Coding Decoding Reasoning

Coding Decoding is very important topic of Reasoning for Competitive Exams. In SSC CGL, CPO, CHSL. RRB NTPC and UPPPSC PET, NRA CET you will find 3-4 questions from this topic. Coding Decoding Notes with Concepts, Tricks, Examples and Questions with PDF are given in this article.

We will learn all type of Coding Decoding Question, important for Govt Job Competitive Exams. Before, Proceed further, we must remember the letter position from Start and end in English Alphabet. It is important to Solve and speed up Coding / Decoding Reasoning Questions

Trick to Remember Letters Position in English Alphabet

First 4 letters, every body know, therefore no trick required.

Remember word EJOTY, Letters are Multiple of 5

“EJOTY”. Rank of E is 5

  • F for Fix and Fix and “Six” are rhyming words
  • G”. Everybody knows G-7 Nations.
  • H looks like 8
  • In cursive writing, it looks like 9

“EJOTY”. Rank of J is 10

  • J & K = Jammu and Kashmir J-10 & K-11
  • Speak together “L Twelve” Sounds like Homonyms
  • Middle most letter in the series is “M” 26/2 =13
  • November 14 is Children`s Day.
Coding Decoding Reasoning

“EJOTY”. Rank of O is 15

  • Reverse of P looks like 6 – P-16
  • Q – Queen 17 pe Khatra (खतरा)
  • R – Raja, Raja is one year older than Queen / राजा, रानी से एक वर्ष बड़ा है 17+1 = 18
  • UNISSSS – 19 – Stress on S

“EJOTY”. Rank of T is 20 / T-20 Cricket

  • U are a graduate(21) – Graduation at the age of 21
  • V for Victory. two fingers to represent Victory. V- 22
  • 90 degree Anti-clock wise letter “W”, it looks like 3, its rank is “23”.
  • X, it is being divided into four parts. Rank of letter “X” is 24. 

“EJOTY”. Rank of letter “Y” is 25.

  • Z is last Word – 26

Types of Coding Decoding Reasoning

1. Letter to Letter Coding

The letter in the word is replaced by other letter, according to a specific rule.

1.1 Add or Subtract Number same number

In a certain language MYSTERY  is coded as NZTUFSZ. What will be the code of TRANSPORT.

WordM- 13Y-25S-19T-20E-5R-18Y-25
CodeN -14Z-26T-20U-21F-6S-19Z-26

+1 in every letter for the code, therefore,


1.2 Decoding

In a certain language SUPER is coded as TVQFS. UJNF is the code of which word.

SUPER -> S+1 =T, U+1=V, P+1=Q, E+1=F, R+1=S

???????? -> UJNF

U-1=T, J-1=I, N-1=M, F-1 = E = TIME

1.3 Add or Subtract in Sequence

In a certain language DELHI  is coded as CCIDD. What will be the code of MUMBAI.


1.4 Alternate Change

In a certain language SIKKAM  is coded as THLJJL. What will be the code of TRAINING.

CodeT-20H-8L- 12J-10J-10L-12

1.5 Reverse the order

In a certain language MONKEY  is coded as XDJMNL. What will be the code of TIGER.
एक निश्चित भाषा में “MONKEY” को “XDJMNL” के रूप में लिखा जाता है। फिर “TIGER” शब्द के लिए कोड क्या होगा

Code in ReversLNMJDX


Code in ReversSHFDQ

Code of TIGER is QDFHS

1.6 Same Letters in the code

In a certain language FASHION  is coded as FOIHSAN. What will be the code of PROBLEM.


First and Last letter are same and remaining were from Right to Left


1.7 Divide the big word

In a certain language EDITION  is coded as IDETNOI. What will be the code of MEDICAL.

Total letters -7, divide 3+1+3
Let the 4th letters as it is and Reverse the first 3 and last 3 letters


Same way


1.8 Vowel and Consonant

In a certain language NATURE  is coded as MASUQE. What will be the code of POND.


In such question we will drive code on the basis of previous rule and code of POND -> OOMD, But this may not be in option, than we will think about Vowel.

No Change in Vowel and -1 in Consonant-1-1-1

1.9 Opposite Letters

How to Remembers opposite letters tricks

In a certain language GOD  is coded as TLW. What will be the code of TEMPLE.


Total is 27 ; that means opposite letters. Same way,

TEMPLE is coded with opposite letters- > GVNKOV

2. Letter to Number Coding Decoding Reasoning

2.1 Addition of Letters Position

In a certain language “D”=4, “COVER” = 63. What will be the code of “BASIS”.


D= 4
COVER -> 3+15+22+5+18 = 63

Same Way

BASIS -> 2+1+19+9+19 = 50

2.2 Multiply the alphabet Position Number

In a certain language “AT”=20, “BAT” = 40. What will be the code of “CAT”.
एक निश्चित भाषा में “AT”=20, “BAT” = 40. “CAT” का कोड क्या होगा।

Solution :

AT = 1×20 =20
BAT = 2x1x20 = 40

Similar manner code of

CAT = 3x1x20 =60

2.3 Add or Subtract Some Number in letter order Number

In a certain language MACHINE = 19-7-9-14-15-20-11. What will be the code of “DANGER “.
एक निश्चित भाषा में MACHINE = 19-7-9-14-15-20-11. “DANGER ” का कोड क्या होगा।



Similar Manner


Code is 10-7-20-13-11-24

2.4 Add the Letter Position Number Digits

In a certain language MOBILITY = 46293927. What will be the code of “EXAMINATION “.



Same Manner


2.5 Number assigned to Individual letter

In such situation, code of all the letters to be find from the given words.

In a certain language PAINT = 53421 and EXCEL = 78679. What will be the code of “ACCEPT “.

Solution :

Look at ACCEPT letters and you will notice all the letters have been used in PAINT and EXCEL.

Pick up Number Code directly from the given word.

A -> 3, C-> 6, E->7, P->5 and T->1

Code of ACCEPT is 366751

3. Substitution Coding

In Substitute Code / Coding questions of Reasoning , some particular objects are assigned code names. Then a question is asked that is to be answered in the code language.


If white is called blue. blue is called red, red is called yellow, yellow is called green, green is called black, black is called violet and violet is called orange, what would be the colour of human blood?

Options : (a) Red (6) Green (c) Yellow,. id) Violet (e) Orange


We know the Colour of blood is Red. From the above statement red is called Yellow
Therefore, Colour of Blood is Yellow – (C)

4. Symbol Coding

In the symbol coding, symbols like “#!?!@$%^&*()_”, to represent words or letters. These codes are then used to determine a code for the given word.

Example: In a certain code, MEAN is written as #57* and DOME is written as 93#5. How is MOAN written in that code?

(a) $ * 37  (b) 3$7* (c) #73 * (d) #37*

Letters              M E A N D O M E

Symbol code    #  5 7  *  9 3 #  5

Hence MOAN Code is #37* (d)

5. Sentence/ Mixed Coding

In Sentence Coding Questions of Reasoning, few Sentences are given with Coded language sentences. The word sequence / order may be change in coded sentence.Words without meaning is code of word with meaning. To solve codes like these remember the order of the numbers may be anything.

Example: In a certain code language, “tee see pee” means ” Drink Fruit Juice”. “see kee jee” means ” Juice is Sweet”, “jee ree mee” means “He is Intelligent”. What is the code for ” Sweet”

Options (a) tee (b) see (c) pee (d) kee


  1. “tee see pee” means ” Drink Fruit Juice”
  2. “see kee jee” means ” Juice is Sweet”
  3. “jee ree mee” means “He is Intelligent”
  • In 1 and 2 Sentence “Juice” and “see” is Common, therefore “see” is code of “Juice”
  • From 2 and 3 rd sentence “Is” is coded as “jee”.
  • Now in 2nd sentence, we know the code of “Juice” and “Is”, therefore, code of “Sweet” is “kee”

Answer is (d)

6. Matrix Coding

A word is represented by only one set of numbers as given in any one of the alternatives. The sets of numbers given in the alternatives are represented by two classes of alphabets as in two matrices given below. The columns and rows of Matrix I are numbered – form 0 to 4 and that Matrix II are numbered from 5 to 9. A letter from these matrices can be represented first by its row and next by its column, e.g., ‘A’ can be represented by 01, 14, etc. and E can be represented by 55, 66 etc. Similarly, you have to identify the set for the word ‘BEST’.

Matrix – I


Matrix – II


(a) 78, 99, 04, 10 (b) 57, 75, 41, 03 (c) 96, 88, 12, 40 (d) 89, 55, 31, 32

Explanation and Solution

Read the instructions and Look at the position of A in Matrix (Colored Red for easy identification)

A is at following 3 Positions

Row -0, Column -1 (01), Row-1, Column -4 (14) and Row 3 Column 0 (30)

Similar Manner E position is (Row, Column) – (55), (66), (77), (88)

Now we have to look for the code for BEST from the available options.

B can be represented (57), (65),(78) and (96)
That Means (a) and (d) are incorrect. and correct answer will be from (c) and (d)

E can be represented by (55), (66), (77), (88)
Only (c) match the condition from (b) and (c)

Therefore Correct Answer is (c)

7. Mathematical Coding Decoding Reasoning

In this type of Coding Questions, digits of a number may be consider individually and Operator symbol work differently.

Examples: 1

In a coded language, 8/3 =4, and 7/6 =2. What is the code of 9/3

Options : (a) 1, (b) 4, (c) 6, (d) 7


8×3 =24 , Take unit digit as code i.e 4
7×6 =42, Take unit digit as code i.e 2

Similar manner 9×3 =27 and unit digit is 7

Answer is (d) 7

Example 2:

2-2 =2, 4-4 =12 and 6-6 =30, what is 8-8 = ?

Options : (a) 12, (b) 42, (c) 60, (d) 56


Square of 2 -2 =4-2 =2
and Square of 4-4 =16-4 = 12
Similarly Square of 6-6 = 36-6 =30

Therefore, Square of 8 -8 = 64-8 = 56, Answer is (d)

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