Coding Decoding is one of the most common topics in the reasoning section of competitive exams like SSC, IBPS, RRB, UPSC, and state-level tests. The questions test your logical thinking, pattern recognition, and decoding ability. With the right tricks and regular practice, you can easily score full marks in this section.
In this blog, you’ll learn all the important types, easy tricks, solved examples, and exam-level practice questions to help you master coding-decoding in 2025.
Introduction: Why Coding Decoding Is Important
In every major government exam, reasoning questions hold high weightage. Coding decoding questions appear in both preliminary and mains exams. This topic is known for being:
- Scoring and quick to solve
- Based on logical patterns and sequences
- Repeated with minor variations in exams
By learning the most asked formats and practicing regularly, you can confidently attempt all questions without wasting time.
Basic to Advanced Coding Decoding Types
There are different types of coding-decoding questions. Let’s go through the most common ones that appear in exams.
1. Letter Coding
Each letter in the word is replaced with another letter using a certain rule or shift.
Example: If WORK is coded as ZRUN, how is HARD coded?
Solution: W(+3) → Z, O(+3) → R, R(+3) → U, K(+3) → N → Rule: +3 shift
H(+3) → K, A(+3) → D, R(+3) → U, D(+3) → G → Answer: KDUG
2. Number Coding
Words are coded using numbers based on position, reverse values, or mathematical logic.
Example: If BAG = 2147, how is CAT coded?
Logic: Use A=1, B=2, C=3, etc.
- B = 2, A = 1, G = 7 → BAG = 2147
- C = 3, A = 1, T = 20 → CAT = 31120
3. Symbol Coding
Every word or letter is represented using symbols.
Example: If ‘APPLE’ is coded as ‘$@#*&’, what is the code for ‘PEAL’?
Solution: Match each letter: P = #, E = , A = $, L = & → **Answer: #$&**
4. Decoding Based on Common Logic
Words or sentences are coded using a logic hidden in a pattern, reverse, or mathematical formula.
Example: If BOY = 25, CAT = 24, DOG = ?
Logic: Add position of letters: D(4)+O(15)+G(7) = 26 → Answer: 26
Shortcut Tricks to Crack Reasoning Questions
Use these smart tricks to solve coding-decoding questions faster:
Trick 1: Alphabet Positioning
- A = 1, B = 2, …, Z = 26
- Reverse: Z = 1, Y = 2, …, A = 26
Trick 2: Observe Shift Patterns
- Look for consistent + or – shifts in letters (e.g., +2, -3)
- Try mapping input-output letter by letter
Trick 3: Compare Multiple Examples
- If 2-3 words are given with codes, find repeating logic or letters
- Eliminate unrelated options first
Trick 4: Use Substitution Tables
Create a table to map letters or numbers if a long sentence is coded.
| Letter | Code |
|---|---|
| A | * |
| B | # |
| C | $ |
Trick 5: Backward Reading
- Check if letters are reversed or placed from end to start
- E.g., ‘RAT’ → ‘TAR’
Top 10 Coding Decoding Questions with Solutions
Here are exam-level practice questions you can try:
Q1. If TREE is coded as USFF, how is LEAF coded?
Answer: MFBG (Each letter +1)
Q2. In a code, MONDAY is written as NPOEBZ. What is SUNDAY?
Answer: TVOEBZ (Each letter +1)
Q3. If COLD = 3-15-12-4, how is WARM coded?
Answer: 23-1-18-13
Q4. If PEN = 16-5-14, then HEN = ?
Answer: 8-5-14
Q5. If GOOD is 71215, what is BAD?
Answer: 214
Q6. If CAT = 24 and DOG = 26, then FOX = ?
Answer: 45
Q7. If ROSE = 6821 and SEAT = 8210, what is EATS?
Answer: 1028
Q8. What comes next in the series: A1, B2, C3, D4, ?
Answer: E5
Q9. If NEWS = 91452319, then WENS = ?
Answer: 14923195
Q10. If S = 19, K = 11, U = 21, what is the sum of S+K+U?
Answer: 51
Topic-wise Coding Decording Practice Set (With Answers)
| Question Type | Example Question | Answer |
| Letter Coding | SKY → TZB | +1 shift |
| Number Coding | PEN = 16514 | Mapping |
| Symbol Coding | CAT → @$# | Match set |
| Substitution Coding | RAT = 321 | Table match |
| Sentence Coding | “I am fine” → “X Y Z” | Word code |
Try creating similar questions to test your understanding.
Mistakes Students Commonly Make in Coding and Decoding Aptitude
In Aptitude, some of the mistakes are commonly made by students, have to look so that you won’t make the same:
- Ignoring basic alphabet positions
- Forgetting reverse logic
- Not comparing letter-by-letter changes
- Rushing through multi-word codes
- Skipping sentence-based coding practice
Avoid these to reduce errors and save time in the exam.
FAQs & Exam Tips
Q1. How many coding and decoding questions are asked in Aptitude?
Usually, 15 to 30 questions appear in the Aptitude test.
Q2. What’s the best way to prepare for this topic?
Practice daily using topic-wise sets, and revise common letter-number mappings.
Q3. Are tricks allowed in exams?
Yes, you should use logical shortcuts—but avoid guesswork.
Q4. Should I skip lengthy questions?
No. Practice speed-reading and identifying logic quickly.
Q5. Can I expect coding-decoding in UPSC?
Yes, basic reasoning sections include such questions in prelims.
Q6. What book or source should I follow?
Use books like R.S. Aggarwal, and daily reasoning quizzes on apps or sites.
Final Thoughts
Coding-Decoding is a scoring topic when prepared smartly. Whether you’re aiming for SSC, IBPS, UPSC, or any state-level exam in 2025, mastering this reasoning section can make a big difference.
Use the tricks shared, solve daily practice questions, and keep your basics clear. For more reasoning guides, free mock tests, and job alerts, follow Thenewviews.com—your trusted exam partner.
Stay ahead. Stay prepared. Crack reasoning like a pro!
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