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Coding-Decoding - Intermediate-Advanced Level: encoding rules INTERMEDIATE-ADVANCED

This fundamentals focus worksheet contains 20 intermediate-advanced-level coding-decoding problems. Worksheet 21 of 30 focuses on encoding rules. Practice encoding rules, decoding techniques, mixed coding with our step-by-step solutions. Difficulty: advanced concepts with increasing complexity. Recommended for advanced developing learners.

📝 Worksheet 21 of 30 • 20 questions • ⏱️ Estimated time: 20 minutes • 🎯 Intermediate-advanced level

What you'll learn in this worksheet:
Your progress through Coding-Decoding
Worksheet 21 of 30 (70% complete)

Question 1

If the code for 'THINK' is 'TH3NK' using the rule 'vowels replaced by numbers (A=1,E=2,I=3,O=4,U=5)', then what is the original word for the code 'TH3NK'?
To decode, replace numbers back to vowels: TH3NK → THINK
decode, reverse

Question 2

If 'HAT' = 29 and 'SUN' = 54, then 'RAT' = ?
Sum of letter positions: HAT = 8+1+20 = 29, SUN = 19+21+14 = 54, RAT = 18+1+20 = 39
position, sum

Question 3

If the code for 'THETA' is 'GSVGZ' using the rule 'each letter replaced by its opposite (A↔Z, B↔Y)', then what is the original word for the code 'GSVGZ'?
To decode, apply opposite again: GSVGZ → THETA
decode, reverse

Question 4

If the code for 'MAP' is 'PDS' using the rule 'each letter shifted forward by 3', then what is the original word for the code 'PDS'?
To decode, shift each letter backward by 3: PDS → MAP
decode, reverse

Question 5

If 'MOUSE' is coded as '73' using the rule 'sum of the positions of all letters', then how is 'MAP' coded?
Sum of positions: MOUSE → 73
arithmetic, operations

Question 6

If 'KEY' = 41 and 'CUP' = 40, then 'BUS' = ?
Sum of letter positions: KEY = 11+5+25 = 41, CUP = 3+21+16 = 40, BUS = 2+21+19 = 42
position, sum

Question 7

If the code for 'CUBE' is 'C5B2' using the rule 'vowels replaced by numbers (A=1,E=2,I=3,O=4,U=5)', then what is the original word for the code 'C5B2'?
To decode, replace numbers back to vowels: C5B2 → CUBE
decode, reverse

Question 8

If the code for 'LID' is 'DIL' using the rule 'reverse the word', then what is the original word for the code 'DIL'?
To decode, reverse the word: DIL → LID
decode, reverse

Question 9

If 'ALPHA' is coded as 'ZSKOZ' using the rule 'replace each letter with its opposite (A↔Z, B↔Y), then reverse', what is the code?
Step 1: Opposite ALPHA → ZOKSZ, Step 2: Reverse → ZSKOZ
mixed, complex

Question 10

If the code for 'GREEN' is 'HSFFO' using the rule 'each letter shifted forward by 1', then what is the original word for the code 'HSFFO'?
To decode, shift each letter backward by 1: HSFFO → GREEN
decode, reverse

Question 11

If 'PEN' is coded as 'UJS' using the rule 'add 5 to each letter's position' (A=1, B=2, ..., Z=26, wrap around), then how is 'PUZZLED' coded?
Each letter position +5: PEN → UJS
arithmetic, operations

Question 12

If the code for 'BETA' is 'GJYF' using the rule 'each letter shifted forward by 5', then what is the original word for the code 'GJYF'?
To decode, shift each letter backward by 5: GJYF → BETA
decode, reverse

Question 13

If 'WIND' is coded as 'XJOE' using the rule 'add 1 to each letter's position' (A=1, B=2, ..., Z=26, wrap around), then how is 'STORAGE' coded?
Each letter position +1: WIND → XJOE
arithmetic, operations

Question 14

If A=1, B=2, C=3... Z=26, then 'EXAM' is coded as?
Converting each letter to its position number: E=5, X=24, A=1, M=13 → 524113
numbers, substitution

Question 15

If 'TABLE' is coded as 'ELBAT', then how is 'WALL' coded?
The pattern is reverse coding: TABLE → ELBAT, so WALL → LLAW
reverse, pattern

Question 16

If 'DECODE' is coded as 'HJFDHJ' using the rule 'multiply each letter's position by 2' (A=1, B=2, ..., Z=26, wrap around), then how is 'CAR' coded?
Each letter position ×2: DECODE → HJFDHJ
arithmetic, operations

Question 17

If A=1, B=2, C=3... Z=26, then 'EXAM' is coded as?
Converting each letter to its position number: E=5, X=24, A=1, M=13 → 524113
numbers, substitution

Question 18

In a certain code, each consonant is replaced by the previous letter (B→A, C→B, etc.). How is 'PROBLEM' coded?
Consonants shifted backward: PROBLEM → OQOAKEL
conditional, vowels

Question 19

If 'CAR' is coded as 'ECT', then how is 'RAT' coded?
The pattern is shifting each letter by +2. So RAT becomes: R(18→20) → A(1→3) → T(20→22) = TCV
shift, basic

Question 20

In a certain code, vowels become next consonant, consonants become next vowel. How is 'MEMORY' coded?
Swapping vowel/consonant roles: MEMORY → OFOPUA
conditional, vowels
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