Letter Coding Decoding Tricks: Shift, Reverse and Opposite Letter Code Questions for SSC CGL, CHSL

In letter coding-decoding, each letter of a word is changed into another letter by a fixed rule. You find the rule from the given example and apply it to a new word. These letter coding decoding tricks for SSC list the common rules (shift, reverse, opposite and progressive shift) and solved examples.

Common Rules

Method

1. Write the word and its code one below the other.
2. Find the shift of each letter (use the positions).
3. Check whether the shift is the same for all letters or changes.
4. Apply the same rule to the new word.

Solved Examples

Example 1. If CAT is coded as DBU, what is the code of DOG?
Each letter moves +1. D→E, O→P, G→H. The code is EPH.

Example 2. If ROSE is coded as TQUG, what is the code of LILY?
Each letter moves +2. L→N, I→K, L→N, Y→A. The code is NKNA.

Example 3. If MANGO is coded as NBOHP, what is the code of APPLE?
Each letter moves +1: A→B, P→Q, P→Q, L→M, E→F. The code is BQQMF.

Example 4 (opposite letters). Find the opposite letter code of MAN.
M↔N, A↔Z, N↔M. The code is NZM.

Example 5 (progressive). If the 1st letter moves +1, the 2nd +2 and the 3rd +3, what is the code of BAG?
B+1 = C, A+2 = C, G+3 = J. The code is CCJ.

Tips

• Learn the positions of the letters (EJOTY) to find a shift quickly.
• Opposite letters add up to 27.
• If a shift crosses Z, start from A again.
• Check the rule on all the letters of the example and not only the first.

Quick Tips

• Check the shift of every letter of the example.
• Use 27 for the opposite letters.
• Wrap around after Z.
• Check progressive shifts when the shift is not equal.

Quick Revision Points

• Shift means moving by the same number of positions.
• The opposite letter of a letter at position p is at 27 − p.
• The reverse code writes the letters in reverse order.
• A progressive shift changes by 1 each time.
• Test the rule on the whole example.

Practice Questions With Answers

1. If CAT is coded as DBU, what is the code of DOG?
   Answer: EPH
2. If ROSE is coded as TQUG, what is the code of LILY?
   Answer: NKNA
3. If MANGO is coded as NBOHP, what is the code of APPLE?
   Answer: BQQMF
4. Write the reverse of the word PEN as a code.
   Answer: NEP
5. What is the opposite letter code of MAN?
   Answer: NZM
6. Each letter is moved back by 1. What is the code of DOG?
   Answer: CNF
7. Each letter is moved forward by 2. What is the code of SKY?
   Answer: UMA
8. If the letters move +1, +2, +3, what is the code of BAG?
   Answer: CCJ
9. If DAD is coded as EBE, what is the code of MOM?
   Answer: NPN
10. What is the first step in a letter coding question?
    Answer: Find the rule between the word and its code

How to Practise This Chapter

Practise 10 questions every day and write the steps on paper. Then attempt timed sets from our practice papers and the previous year papers page. See all topics on the Verbal Reasoning notes page, read the previous topic Letter Cluster Series and the next topic Word Analogy. Learn the letter positions from the Alphabet Test note first. Also read Coding-Decoding.

Frequently Asked Questions

What is letter coding in reasoning?

It is a question in which the letters of a word are changed into other letters by a rule.

How do I find the rule?

Write the word and the code below each other and find the shift of each letter.

What is a shift code?

A code in which each letter moves forward or backward by the same number.

What is the opposite letter code?

Each letter is replaced by its opposite letter in the alphabet, like A by Z.

How do I find the opposite letter?

Subtract the position from 27.

What is a progressive shift?

The shift changes for each letter, such as +1, +2, +3.

What happens after Z?

The letters wrap around and start from A.

Is letter coding asked in SSC exams?

Yes. Coding-decoding is asked in SSC CGL, CHSL and MTS.

How much time should I take?

About 30 seconds.

What are the common mistakes?

Checking only the first letter of the example.

How can I improve my speed?

Learn the position table and practise 10 questions daily.

What is the difference between letter and number coding?

Letter coding gives letters, and number coding gives numbers as the code.