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Coding-Decoding & Symbolic Operations

Reasoning & General Intelligence — Paper-I · Official 2026 Coverage

Useful for: SSC CGL

Overview

Tier-II coding uses progressive shifts, mixed rules and symbol substitution with BODMAS.

Key points

Progressive shifts: +2, +3, +4, … by position.
Reverse-order coding with shifts.
Number codes from position sums or products.
Symbol substitution: rewrite fully, then apply BODMAS.
Conditional coding: apply the first matching condition.

Explanation

Write positions above letters to see the shift pattern.
Check whether the code is applied to the reversed word.
Verify the rule on at least two letters before applying.
For symbol inequalities, combine relations through a common term.

Step by step

Identify the pattern, rule or relationship.
Apply it carefully to the question part.
Verify against every condition before marking.

Examples

FRIEND → HUMJTK (+2, +3, +4, +5, +6, +7), so CANDLE → EDRIRL.
If "×" means "+" and "+" means "×", then 5 × 4 + 3 = 5 + 4 × 3 = 17.
If CAT = 24 (sum of positions), then BAT = 2 + 1 + 20 = 23.

Traps and advanced points

Trap: Assuming a constant shift.
Trap: Calculating with original symbols.
Trap: Ignoring reversal.

Quick revision

Shift table per position.
Rewrite before BODMAS.
Test two letters.

Practice MCQs

If the coding rule reverses the letters, how is DQHOVC coded?
1. DQHOVC
2. QHOVCD
3. CVOHQD
4. ERIPWD
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Answer: (c) CVOHQD. DQHOVC reversed is CVOHQD.
In a code, HMRWB is written as MRWBG. How will DGJMP be written?
1. YBEHK
2. ILORU
3. JMPSV
4. HKNQT
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Answer: (b) ILORU. Apply +5 to each letter of DGJMP: ILORU.
In a code, TYDIN is written as WBGLQ. How will FILOR be written?
1. HKNQT
2. CFILO
3. JMPSV
4. ILORU
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Answer: (d) ILORU. Apply +3 to each letter of FILOR: ILORU.
In a code, EJOTY is written as GLQVA. How will WZCFI be written?
1. UXADG
2. ZCFIL
3. YBEHK
4. XADGJ
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Answer: (c) YBEHK. Apply +2 to each letter of WZCFI: YBEHK.
In a code, OTYDI is written as SXCHM. How will CFILO be written?
1. HKNQT
2. FILOR
3. GJMPS
4. YBEHK
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Answer: (c) GJMPS. Apply +4 to each letter of CFILO: GJMPS.
If the coding rule reverses the letters, how is CGJQXE coded?
1. GJQXEC
2. CGJQXE
3. DHKRYF
4. EXQJGC
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Answer: (d) EXQJGC. CGJQXE reversed is EXQJGC.
In a code, DINSX is written as INSXC. How will LORUX be written?
1. QTWZC
2. RUXAD
3. GJMPS
4. PSVYB
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Answer: (a) QTWZC. Apply +5 to each letter of LORUX: QTWZC.
In a code, AFKPU is written as DINSX. How will EHKNQ be written?
1. GJMPS
2. ILORU
3. BEHKN
4. HKNQT
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Answer: (d) HKNQT. Apply +3 to each letter of EHKNQ: HKNQT.
In a code, AFKPU is written as EJOTY. How will EHKNQ be written?
1. HKNQT
2. JMPSV
3. ADGJM
4. ILORU
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Answer: (d) ILORU. Apply +4 to each letter of EHKNQ: ILORU.
In a code, AFKPU is written as FKPUZ. How will EHKNQ be written?
1. ILORU
2. ZCFIL
3. KNQTW
4. JMPSV
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Answer: (d) JMPSV. Apply +5 to each letter of EHKNQ: JMPSV.