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Number Substitution

Number Substitution problems replace each letter with its position number in the alphabet (A=1, B=2, ..., Z=26). Words become sequences of numbers. Some variations use A=0, B=1, or reverse numbering (A=26, B=25). These problems test your knowledge of alphabet positions and quick conversion.

10Worksheets
200+Practice Questions
BeginnerDifficulty
1-2 hoursHours to Master

What You'll Learn

Introduction & Overview Why This Matters How to Solve Pro Tips & Tricks
Shortcut Methods Common Mistakes Practice Worksheets Exam Importance

Introduction to Number Substitution

Number Substitution problems replace each letter with its position number in the alphabet (A=1, B=2, ..., Z=26). Words become sequences of numbers. Some variations use A=0, B=1, or reverse numbering (A=26, B=25). These problems test your knowledge of alphabet positions and quick conversion.

Prerequisites

Alphabet positions (A=1 to Z=26) Memorization of key positions Basic number writing Quick recall of letter-number mapping
Why This Matters: Number Substitution problems appear in 2-3 questions in SSC CGL and Banking PO exams. They test basic alphabet position knowledge.

How to Solve Number Substitution Problems

1

Step 1: Identify the mapping scheme (A=1, B=2, ... or A=0, B=1, ... or A=26, B=25, ...)

2

Step 2: Convert each letter of the given word to its corresponding number

3

Step 3: Write the numbers in the same order as the letters

4

Step 4: For reverse coding, convert each number back to its letter

5

Step 5: Verify the mapping is consistent for all letters

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Step 6: Answer with the coded number sequence or decoded word

Pro Strategy: Memorize the alphabet position numbers for quick conversion. Practice common words to build speed. For three-letter words, combine numbers into a single number (e.g., CAT = 3,1,20 = 3120).

Example Problem

Example 1: If A=1, B=2, C=3, ... Z=26, code 'BED'. Solution: Step 1: B=2, E=5, D=4 Step 2: Code = 2,5,4 or 254 Answer: 254 Example 2: If 1=A, 2=B, ... 26=Z, decode '12,1,20'. Solution: 12=L, 1=A, 20=T → LAT Answer: LAT

Pro Tips & Tricks

  • A=1, B=2, C=3, D=4, E=5, F=6, G=7, H=8, I=9, J=10, K=11, L=12, M=13
  • N=14, O=15, P=16, Q=17, R=18, S=19, T=20, U=21, V=22, W=23, X=24, Y=25, Z=26
  • Vowels: A=1, E=5, I=9, O=15, U=21
  • M=13 (middle), N=14 (middle+1)
  • For A=26, B=25 scheme: position = 27 - original position
  • Two-digit numbers (10-26) are written as is, not as separate digits

Shortcut Methods to Solve Faster

A=1, E=5, I=9, O=15, U=21 (vowels are odd numbers)
Z=26, Y=25, X=24 (reverse order from Z)
To decode quickly, know that 1-26 map directly to A-Z
For A=0 scheme: subtract 1 from each position

Common Mistakes to Avoid

Using A=0 instead of A=1 (common variant, check the problem)
Confusing two-digit numbers (e.g., 11 vs 1,1)
Forgetting to maintain letter order
Miscalculating positions for letters near the end of alphabet

Exam Importance

Number Substitution is an important topic for various competitive exams. Here's how frequently it appears:

SSC CGL
2-3 questions
BANKING PO
2-3 questions
RAILWAYS RRB
2-3 questions
CAT
1-2 questions
INSURANCE
2-3 questions

Ready to Master Number Substitution?

Start with Worksheet 1 and work your way up to expert level! Each worksheet includes:

20 practice questions
Detailed solutions
Step-by-step explanations
Start Practicing Now