Login
OR
Don't worry. We'll fix this for you!
Coding-Decoding is a fundamental topic in verbal reasoning that tests your ability to understand and manipulate patterns in words and symbols. In competitive exams, questions on coding-decoding assess your logical thinking, attention to detail, and analytical skills. The basic idea is simple: a word or phrase is transformed into a code using a specific rule or pattern, and you must either find the code for a given word or decode a given code back to the original word.
Understanding coding-decoding helps you sharpen your problem-solving skills and prepares you for a variety of question types in exams. This section will guide you from the very basics to advanced techniques, ensuring you can confidently tackle any coding-decoding problem.
Before solving coding-decoding problems, it is essential to know the common types of coding methods used. These methods define how words are converted into codes.
| Word | Letter Coding (Shift by +1) | Number Coding (Alphabet Position) | Mixed Coding (Letter + Number) |
|---|---|---|---|
| CAT | DBU (C->D, A->B, T->U) | 3-1-20 | C3A1T20 |
| DOG | EPH | 4-15-7 | D4O15G7 |
| BAT | CBU | 2-1-20 | B2A1T20 |
Letter Coding: Each letter in the word is shifted forward or backward by a fixed number in the alphabet. For example, shifting each letter by +1 means A becomes B, B becomes C, and so on.
Number Coding: Each letter is replaced by its position in the English alphabet (A=1, B=2, ..., Z=26). For example, CAT becomes 3-1-20.
Mixed Coding: Combines letters and numbers, such as writing the letter followed by its numeric position.
Decoding means reversing the coding process to find the original word from the code. Here are systematic steps to decode efficiently:
graph TD A[Identify the code type] --> B[Look for letter shifts or substitutions] B --> C{Is it a letter shift?} C -- Yes --> D[Shift letters backward by the same number] C -- No --> E{Is it number coding?} E -- Yes --> F[Convert numbers to letters using alphabet positions] E -- No --> G[Check for rearrangement or symbol substitution] D --> H[Form the decoded word] F --> H G --> H H --> I[Verify if the word is meaningful]Following these steps helps avoid confusion and speeds up solving coding-decoding problems.
Step 1: Identify the position of each letter in the alphabet.
C = 3, A = 1, T = 20
Step 2: Shift each letter two places forward.
3 + 2 = 5 -> E
1 + 2 = 3 -> C
20 + 2 = 22 -> V
Step 3: Write the encoded word.
Encoded word = ECV
Answer: ECV
Step 1: Convert each number to its corresponding letter.
3 -> C
1 -> A
20 -> T
Step 2: Combine the letters to form the word.
Decoded word = CAT
Answer: CAT
Step 1: Analyze the given code.
Original: Z E B R A
Coded: Y D C Q Z
Step 2: Find the letter shifts.
Z -> Y (shift -1)
E -> D (shift -1)
B -> C (shift +1)
R -> Q (shift -1)
A -> Z (shift -1)
Observation: Except for B -> C (+1), all others shifted backward by 1.
Step 3: Check letter rearrangement.
Positions changed: The last letter A coded as Z at the end.
It appears letters are shifted mostly by -1, with a rearrangement of the last letter to the front.
Step 4: Apply the same rule to TIGER.
T I G E R
Shift each letter by -1:
T -> S
I -> H
G -> F
E -> D
R -> Q
Rearrange last letter to front: Q S H F D
Answer: QSHFD
Step 1: Identify symbols and replace them with vowels.
# -> E
@ -> A
Step 2: Replace symbols in the code.
H # L L @ -> H E L L A
Answer: HELLA
Step 1: Decode each code by shifting letters backward by 2.
FQI -> D O G (correct)
ECV -> C A T (correct)
DBV -> B C T (incorrect, expected BAT)
TCV -> R A T (correct)
Step 2: Identify the odd code.
Code 3 (DBV) is incorrect because the middle letter shifted incorrectly.
Answer: Code 3 is the odd one out.
When to use: When the code involves letter or number substitution.
When to use: When letters appear jumbled or out of order.
When to use: When multiple choice options are given.
When to use: For number substitution based coding.
When to use: To improve speed and accuracy during exams.
Progress tracking is paywalled — subscribe to mark subtopics as understood and save your streak.
Go to practice →
Your Score
Your Rank
| Rank | Name | Score |
|---|