SSC Reasoning: Coding-Decoding Complete Guide
SSC Exams

SSC Reasoning: Coding-Decoding Complete Guide

Coding-Decoding is one of the most frequently asked topics in the Reasoning section of SSC exams. This comprehensive guide will help you understand all types of coding-decoding patterns and master the shortcuts to solve them quickly.

What is Coding-Decoding?

Coding-Decoding involves converting a word, number, or phrase into a different form based on certain rules or patterns. The main objective is to identify the pattern and apply it to decode or encode the given information.

Types of Coding-Decoding

1. Letter Coding

In this type, letters are coded with other letters based on their position in the alphabet.

Example: If PLANT is coded as QMBOU, what is the code for GARDEN? Solution: Each letter is shifted by +1 position (P→Q, L→M, A→B, N→O, T→U) So GARDEN would be coded as HBSEFO.

2. Number Coding

Letters are assigned numerical values based on their alphabetical positions.

Example: If A=1, B=2, C=3… then HELLO = 8+5+12+12+15 = 52

3. Substitution Coding

Specific words are given codes that need to be memorized and applied.

Example:

  • DOG is coded as 123
  • CAT is coded as 456
  • What is the code for GOD? Answer: 321

Important Patterns to Remember

Pattern 1: Forward/Backward Shift

  • Forward shift: A→B, B→C, C→D
  • Backward shift: A→Z, B→A, C→B

Pattern 2: Opposite Letter Coding

A↔Z, B↔Y, C↔X, D↔W… and so on.

Pattern 3: Position-Based Coding

Based on position in alphabet:

  • A=1, B=2, C=3… Z=26
  • Or reverse: A=26, B=25, C=24… Z=1

Quick Solving Techniques

Technique 1: Pattern Recognition

  1. Compare the given word with its code
  2. Find the common pattern
  3. Apply the same pattern to the question

Technique 2: Alphabet Positions

Remember: A=1, B=2… Z=26 Use this for quick calculations.

Technique 3: Opposite Letters

A-Z, B-Y, C-X, D-W, E-V, F-U, G-T, H-S, I-R, J-Q, K-P, L-O, M-N

Practice Questions

Question 1:

If COMPUTER is coded as RFUVQNPC, then NOTEBOOK is coded as? Answer: UNCROYUM

Question 2:

In a certain code, REMOTE is written as DSLPKF. How is SENSOR written in that code? Answer: RFOLND

Question 3:

If FRIEND is coded as HUMJTK, then CANDLE is coded as? Answer: EDRNGF

Common Mistakes to Avoid

  1. Not identifying the pattern correctly - Take time to analyze
  2. Confusion between forward and backward shifts
  3. Arithmetic errors in position calculations
  4. Not considering opposite letter pairs

Exam Strategy

Time Management:

  • Spend 1-2 minutes identifying the pattern
  • Apply the pattern quickly
  • Double-check your answer

Difficulty Levels:

  • Easy: Simple forward/backward shifts
  • Medium: Mixed patterns, number coding
  • Hard: Complex substitution, multiple patterns

Expected Questions in SSC Exams

  • SSC CGL: 2-3 questions (Tier-I)
  • SSC CHSL: 1-2 questions
  • SSC MTS: 1-2 questions
  • SSC CPO: 2-3 questions

Preparation Tips

  1. Practice daily - Solve 10-15 questions every day
  2. Learn patterns - Memorize common coding patterns
  3. Time yourself - Practice with time constraints
  4. Analyze mistakes - Understand why you went wrong

With consistent practice and understanding of patterns, coding-decoding can become one of your strongest topics in the reasoning section!