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Basic Letter-Number

Basic Letter-Number Coding replaces each letter with its position in the English alphabet (A=1, B=2, C=3, ..., Z=26). Words become sequences of numbers. Some variations use A=0, B=1, or reverse numbering (A=26, B=25). These foundational problems test your knowledge of alphabet positions and quick conversion skills.

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 Basic Letter-Number

Basic Letter-Number Coding replaces each letter with its position in the English alphabet (A=1, B=2, C=3, ..., Z=26). Words become sequences of numbers. Some variations use A=0, B=1, or reverse numbering (A=26, B=25). These foundational problems test your knowledge of alphabet positions and quick conversion skills.

Prerequisites

Alphabet positions (A=1 to Z=26) Memorization of key positions Basic number writing Quick recall of letter-number mapping
Why This Matters: Basic Letter-Number Coding is the most fundamental coding-decoding problem type. You can expect 2-3 questions in SSC CGL, 2-3 in Banking PO, and 2-3 in Railways RRB exams.

How to Solve Basic Letter-Number Problems

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

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

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

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

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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

Ready to Master Basic Letter-Number?

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