Coding-Decoding Basics

Coding = Converting words/numbers into a specific pattern Decoding = Finding the original word/number from the code

Types of Coding-Decoding

1. Letter Coding - Forward/Backward shifts
2. Number/Symbol Coding - Letters replaced by numbers
3. Substitution Coding - Words replaced by other words
4. Mixed Coding - Combination of above

Letter Coding

Type 1: Forward Shift

Example: If BOOK is coded as CPPL, how is PENCIL coded?

Solution:

B → C (shift +1)
O → P (shift +1)
O → P (shift +1)
K → L (shift +1)

Similarly:
PENCIL → QFODJM

Type 2: Reverse Alphabet

Example: If A=Z, B=Y, C=X… then EXAM = ?

Solution:

E (5th letter) → V (22nd letter)
X (24th letter) → C (3rd letter)
A (1st) → Z (26th)
M (13th) → N (14th)

EXAM → VCZN

Shortcut: Position from start + Position from end = 27

Number Coding

Example: If CAT = 24, DOG = 26, find PIG = ?

Solution:

CAT: C=3, A=1, T=20 → 3+1+20 = 24
DOG: D=4, O=15, G=7 → 4+15+7 = 26
PIG: P=16, I=9, G=7 → 16+9+7 = 32

Answer: 32

Important Alphabet Positions

Memorize these for speed:

Quick Tricks

1. Find the pattern first - Addition, subtraction, or substitution
2. Check all letters - Pattern should be consistent
3. Use alphabet positions - A=1, B=2… memorize till M=13

Additional Resources

• Blood Relations Practice →
• Series Completion Questions →
• Reasoning Mock Tests →

💡 Study Tip: Coding-Decoding is pure pattern recognition. Practice 30-40 questions to master all types!