Coding and Decoding Aptitude Questions: Tips, Tricks, and Practice

Practicing different types of coding decoding questions reasoning is the best way to master coding and decoding.

1. Letter Coding Example

Question:
If “CAT” is coded as “DBU,” how is “DOG” coded in the same way?

Solution:
Let’s find the pattern:

• C → D (shifted +1)
• A → B (shifted +1)
• T → U (shifted +1)

Apply the same logic to “DOG”:

• D → E
• O → P
• G → H

Answer:
“DOG” is coded as “EPH”.

2. Number Coding Example

Question:
If “SEND” is coded as 168, what is the code for “WORD” using the same logic?

Solution:
From the article, the logic is:
Sum the alphabetical positions of the letters and multiply by the number of letters.

SEND: S(19) + E(5) + N(14) + D(4) = 19 + 5 + 14 + 4 = 42
42 × 4 = 168

Now for WORD: W(23) + O(15) + R(18) + D(4) = 23 + 15 + 18 + 4 = 60
60 × 4 = 240

Answer:
“WORD” is coded as 240.

3. Mixed Coding Example

Question:
In a certain code language:

• “sky is blue” is written as “pa ni lo”
• “blue and green” is written as “lo ti sa”
• “sky and cloud” is written as “pa sa ri”

What is the code for “and”?

Solution:
Look for the common word and code:

• “blue and green” and “sky and cloud” both have “and”
• The common code in “lo ti sa” and “pa sa ri” is “sa”

Answer:
“and” is coded as “sa”.

4. Sequence Coding Example

Question:
If the word “LEMON” is coded as “ELMNO” (letters arranged alphabetically), how is “ORANGE” coded in the same way?

Solution:
Arrange the letters of “ORANGE” in alphabetical order:
A, E, G, N, O, R

Answer:
“ORANGE” is coded as “AEGNOR”.

5. Letter Coding

Question:
If “BIRD” is coded as “CJSE,” how is “FISH” coded?

Solution:
Pattern: Each letter is shifted +1, +2, +3, +4 respectively.
B(+1)=C, I(+2)=J, R(+3)=S, D(+4)=E
Apply to FISH:
F(+1)=G, I(+2)=K, S(+3)=V, H(+4)=L
Answer:
“FISH” is coded as “GKVL”.

6. Number Coding

Question:
If “APPLE” is coded as 50, what is the code for “MANGO”?

Solution:
A(1)+P(16)+P(16)+L(12)+E(5) = 1+16+16+12+5 = 50
M(13)+A(1)+N(14)+G(7)+O(15) = 13+1+14+7+15 = 50
Answer:
“MANGO” is coded as 50.

7. Mixed Coding

Question:
“day is bright” = “ka la ma”
“night is dark” = “pa la sa”
“bright and dark” = “ma ta sa”
What is the code for “dark”?

Solution:
“night is dark” and “bright and dark” share “dark” and “sa”.
Answer:
“dark” is coded as “sa”.

8. Sequence Coding

Question:
If “TABLE” is coded as “ABELT”, how is “CHAIR” coded?

Solution:
Alphabetical order: A, C, H, I, R
Answer:
“CHAIR” is coded as “ACHIR”.

9. Letter Coding

Question:
If “DOG” is coded as “FQI”, how is “CAT” coded?

Solution:
D(+2)=F, O(+2)=Q, G(+2)=I
C(+2)=E, A(+2)=C, T(+2)=V
Answer:
“CAT” is coded as “ECV”.

10. Number Coding

Question:
If “BALL” is coded as 30, what is the code for “CALL”?

Solution:
B(2)+A(1)+L(12)+L(12)=27
C(3)+A(1)+L(12)+L(12)=28
Pattern: Add 3 to the sum for code.
BALL: 27+3=30, CALL: 28+3=31
Answer:
“CALL” is coded as 31.

11. Mixed Coding

Question:
“green grass grows” = “ta pa la”
“grass is green” = “la sa ta”
“sun grows grass” = “ma pa la”
What is the code for “grass”?

Solution:
Common in all: “grass” and “la”
Answer:
“grass” is coded as “la”.

12. Sequence Coding

Question:
If “WORLD” is coded as “DLROW”, how is “EARTH” coded?

Solution:
Reverse the word: H, T, R, A, E
Answer:
“EARTH” is coded as “HTRAE”.

13. Letter Coding

Question:
If “MOON” is coded as “NPOO”, how is “STAR” coded?

Solution:
First letter moved to the end.
S→TAR S, T→ARS T, A→RS A, R→S R
So, “STAR” becomes “TARS”.
Answer:
“STAR” is coded as “TARS”.

14. Number Coding

Question:
If “HOME” is coded as 36, what is the code for “DOME”?

Solution:
H(8)+O(15)+M(13)+E(5)=41
Pattern: Subtract 5
HOME: 41-5=36, DOME: D(4)+O(15)+M(13)+E(5)=37, 37-5=32
Answer:
“DOME” is coded as 32.

15. Mixed Coding

Question:
“red rose blooms” = “pa la sa”
“white rose fresh” = “ta la ma”
“fresh red wine” = “ma pa na”
What is the code for “rose”?

Solution:
Common in first two: “rose” and “la”
Answer:
“rose” is coded as “la”.

16. Sequence Coding

Question:
If “PEAR” is coded as “AEPR”, how is “GRAPE” coded?

Solution:
Alphabetical order: A, E, G, P, R
Answer:
“GRAPE” is coded as “AEGPR”.

17. Letter Coding

Question:
If “FIRE” is coded as “GJTG”, how is “WATER” coded?

Solution:
Each letter +1, -1, +1, -1:
F(+1)=G, I(-1)=H, R(+1)=S, E(-1)=D
W(+1)=X, A(-1)=Z, T(+1)=U, E(-1)=D, R(+1)=S
Answer:
“WATER” is coded as “XZUDS”.

18. Number Coding

Question:
If “MATH” is coded as 40, what is the code for “PATH”?

Solution:
M(13)+A(1)+T(20)+H(8)=42
Subtract 2: 42-2=40
PATH: P(16)+A(1)+T(20)+H(8)=45, 45-2=43
Answer:
“PATH” is coded as 43.

19. Mixed Coding

Question:
“sky is blue” = “ka la ma”
“sea is deep” = “ta la pa”
“deep blue sky” = “pa ma ka”
What is the code for “deep”?

Solution:
Common in second and third: “deep” and “pa”
Answer:
“deep” is coded as “pa”.

20. Sequence Coding

Question:
If “BANANA” is coded as “AAABNN”, how is “ORANGE” coded?

Solution:
Alphabetical order: A, E, G, N, O, R
Answer:
“ORANGE” is coded as “AEGNOR”.

21. Letter Coding

Question:
If “GAME” is coded as “HBNF”, how is “PLAY” coded?

Solution:
Each letter +1:
P→Q, L→M, A→B, Y→Z
Answer:
“PLAY” is coded as “QMBZ”.

22. Number Coding

Question:
If “TREE” is coded as 56, what is the code for “FREE”?

Solution:
T(20)+R(18)+E(5)+E(5)=48
Pattern: Add 8
TREE: 48+8=56
FREE: F(6)+R(18)+E(5)+E(5)=34, 34+8=42
Answer:
“FREE” is coded as 42.

23. Mixed Coding

Question:
“cold wind blows” = “la ma sa”
“wind and rain” = “ma ta pa”
“rain is cold” = “pa la ka”
What is the code for “wind”?

Solution:
Common in first and second: “wind” and “ma”
Answer:
“wind” is coded as “ma”.

24. Sequence Coding

Question:
If “SCHOOL” is coded as “CHLOOS”, how is “COLLEGE” coded?

Solution:
Alphabetical order: C, E, E, G, L, L, O
Answer:
“COLLEGE” is coded as “CEEGLLO”.

25. Letter Coding

Question:
If “MOUSE” is coded as “NPTVF”, how is “HOUSE” coded?

Solution:
Each letter +1:
H→I, O→P, U→V, S→T, E→F
Answer:
“HOUSE” is coded as “IPVTF”.

Key Takeaways So Far

• Practice with real examples builds familiarity with common patterns.
• Solutions help you understand the step-by-step logic.
• Exposure to a variety of question types boosts confidence.

Solving coding decoding aptitude test questions can seem daunting at first, but a systematic approach can make the process much simpler and faster.

1. Read the Question Carefully
   Pay close attention to the given words, codes, and instructions. Make sure you understand exactly what is being asked.
2. Identify the Pattern
   Look for patterns in the way letters or numbers are changed. Common patterns include:
   
   • Shifting letters forward or backward in the alphabet
   • Reversing the order of letters
   • Replacing letters with their alphabetical positions
   • Applying mathematical operations to numbers
3. Compare Multiple Examples
   If more than one coded pair is given, compare them to confirm the pattern. The logic should work consistently across all examples.
4. Test Your Logic
   Apply your identified rule to other examples in the question to ensure it holds true. If it doesn’t, re-examine the data for a different pattern.
5. Apply the Rule to the Target Word or Number
   Once you’re confident in the pattern, use it to encode or decode the required word, number, or sentence.
6. Double-Check Your Answer
   Quickly review your steps to make sure you haven’t missed any detail or made a calculation error.
7. Practice Regularly
   The more you practice, the faster you’ll spot patterns and solve coding decoding aptitude questions with answers accurately under exam conditions.

This step-by-step guide provides a logical process, making it easier for readers to approach any aptitude test coding and decoding question with clarity and confidence.