Coding-Decoding Questions for SSC GD

Letter Shifting (Forward and Backward)

Each letter in the word is shifted by a fixed number of positions in the alphabet. If A=1, B=2 ... Z=26, then shifting CAT by +2 gives ECV. SSC GD loves shifts of +1, +2, +3, -1, -2. Also watch for reverse alphabet coding where A=26, B=25, Z=1. Think of the alphabet as a number line and just slide each letter left or right.

• Learn positions: A=1, B=2, C=3 ... M=13, N=14 ... Z=26
• Reverse alphabet: A=26, B=25 ... Z=1 (opposite end trick)
• If shift goes beyond Z, it wraps around to A again
• Identify the shift by comparing one known letter in question to its code
• Same shift applies to ALL letters in the same question

Number Substitution Coding

Letters are replaced by numbers based on a rule — could be their alphabet position, reversed position, or a calculated value. For example, CAT = 3+1+20 = 24, or each letter is coded as its position squared. SSC GD usually keeps math simple — addition of positions, or direct position values. Spot the rule using the given example word, then apply same rule to the question word.

• First check: is it simply A=1, B=2 position coding?
• Second check: is it reverse position A=26, B=25?
• Third check: is it position + some fixed number like A=3, B=4 (shift by 2)?
• Sometimes each letter's value is added to give one number for the whole word
• Always verify your found rule with the second given example before answering

Word-to-Word or Symbol Coding

A complete word is coded as another word or symbol. There is no mathematical shift — it is a fixed dictionary substitution. SSC GD gives two or three coded sentences and asks you to find the code for a specific word. The trick is to find the word that appears in all sentences and match the code that also repeats.

• Look for the word that appears in exactly TWO given sentences
• The code word that also appears in those same two sentences is its code
• Eliminate by checking which code word does NOT appear elsewhere
• Order of code words may not match order of original words
• If only one sentence is given, look for the specific word and match position

Odd-Position and Mixed Pattern Coding

Some questions reverse only certain letters, swap pairs, or apply different rules to odd and even positions. For example, only consonants shift by +1 while vowels stay same, or letters at odd positions shift forward and even positions shift backward. SSC GD occasionally uses this as a difficult variant. Identify by checking if a single rule explains all letters — if not, look for a two-rule pattern.

• Test your identified rule on every letter — if one letter breaks the rule, there are two rules
• Common mixed patterns: odd positions forward, even positions backward
• Another pattern: first half of word is reversed, second half coded normally
• In SSC GD these are rare but appear as the hardest question in the set
• Skip and come back if you cannot spot pattern in 30 seconds

Reverse Word Coding

The simplest and fastest type. The entire word is just written backwards. KING becomes GNIK. Or each pair of letters is swapped: ABCD becomes BADC. SSC GD uses this as a filler easy question. Spot it instantly by reversing the original word and checking if it matches the code.

• Reverse entire word: ARMY becomes YMRA
• Pair swap: AB CD EF becomes BA DC FE
• Works only for words of even length in pair swap
• Takes under 10 seconds once pattern is spotted
• Always the first pattern to check when no number or big shift is visible

• Forgetting wrap-around: after Z comes A. Many aspirants get stuck on Y+2 and write AA instead of A (Y=25+2=27, 27-26=1=A)
• In word-to-word coding, aspirants match by position instead of finding the repeated word. Never assume position order is preserved.
• Checking the rule on only one letter and answering — always verify on at least two letters before applying
• Confusing forward alphabet position with reverse alphabet position. When in doubt write both A=1 and A=26 rows and check which fits
• In number substitution, treating the number as a shift code instead of a sum code — read the question carefully to know if the code IS a number or if the number IS the shift

• SRNM trick for pattern types: Shift, Reverse, Number, Mixed — try them in this order on every question
• Alphabet mid-point: M=13, N=14. Numbers on left of M decrease toward A, numbers on right of N increase toward Z. Use M and N as anchors when counting.
• For reverse alphabet: just do 27 minus the normal position. A=27-1=26, B=27-2=25. The '27 minus' rule always works.
• Word coding trick: Circle the word asked, find it in two sentences, the code word sitting in both those sentences at any position is your answer — call it the Twin Sentence Method

• SSC GD typically gives 2 to 3 coding-decoding questions per paper. They are usually Easy to Medium level — treat them as guaranteed marks.
• Most common type in recent SSC GD papers is letter shifting (+1 or +2) and number substitution by position sum. Practise these two the most.
• Time limit: spend maximum 40 seconds per question. If not solved in 40 seconds, mark and move on — these questions have no guessing penalty logic, come back fresh.
• Questions sometimes give the code of two words and ask the code of a third. Write the rule explicitly on rough paper — do not try to hold it in your head.
• In mixed and symbol coding, the answer options themselves are a clue. Eliminate options where the known code word appears incorrectly — this shortcut saves 15 seconds per question.