Coding and Decoding

🔐 Coding and Decoding: The Secret Language Adventure

Welcome, Code Breaker!

Imagine you have a secret clubhouse with your best friends. You want to pass notes in class, but you don’t want the teacher to read them. What do you do? You create a secret code!

That’s exactly what Coding and Decoding is all about. It’s like being a spy who can read hidden messages! 🕵️

🎯 What is Coding and Decoding?

Think of it like this:

Coding = Turning a normal message into a secret message Decoding = Turning a secret message back into a normal message

Real-Life Example:

• Your friend writes “APPLE” as “CRRNG”
• Only YOU know how to read it because you know the secret rule!

📚 The Five Types of Secret Codes

graph TD
    A["Coding & Decoding"] --> B["Letter Coding"]
    A --> C["Number Coding"]
    A --> D["Mixed Coding"]
    A --> E["Symbolic Coding"]
    A --> F["Sentence Coding"]

1️⃣ Letter Coding

The Alphabet Shift Game

Imagine the alphabet is a sliding puzzle. You slide all letters by the same number of steps!

The Simple Rule

Each letter becomes another letter by moving forward or backward in the alphabet.

Example: Shift by +2

So “CAT” becomes “ECV”!

How to Solve Letter Coding

Step 1: Look at the given word and its code Step 2: Find how many positions each letter moved Step 3: Apply the same rule to the new word

🎮 Practice Problem

Given: MANGO is coded as OCPIQ Find: How is GRAPE coded?

Solution:

M → O (shift +2)
A → C (shift +2)
N → P (shift +2)
G → I (shift +2)
O → Q (shift +2)

The rule is: Add 2 to each letter

So GRAPE becomes:

G → I
R → T
A → C
P → R
E → G

Answer: ITCRG ✅

🔄 Reverse Letter Coding

Sometimes the code reverses the word first, then shifts!

Example: TIGER → REGIT → TGIKV (after +2 shift)

💡 Pro Tips for Letter Coding

1. Write the alphabet with numbers (A=1, B=2… Z=26)
2. Check if it wraps around (Z+1 = A)
3. Look for patterns in the shift

2️⃣ Number Coding

When Letters Become Numbers

Instead of shifting letters, we replace them with numbers!

The Position Code

The simplest number code uses alphabet positions:

Example: CAT = 3, 1, 20 = 3120 (written together)

🎮 Practice Problem

Given: In a code, FACE = 6135 Find: What is BEAD?

Solution:

F = 6 (F is 6th letter)
A = 1 (A is 1st letter)
C = 3 (C is 3rd letter)
E = 5 (E is 5th letter)

Following the same pattern:

B = 2
E = 5
A = 1
D = 4

Answer: 2514 ✅

🔢 Reverse Number Coding

Sometimes numbers are assigned opposite to positions:

Example: CAT = 24, 26, 7 = 24267

📐 Mathematical Number Coding

Some codes use math operations on positions!

Example: Double the position

A = 1 × 2 = 2
B = 2 × 2 = 4
C = 3 × 2 = 6

So CAT = 6, 2, 40

3️⃣ Mixed Coding

The Ultimate Puzzle

Mixed coding combines letters AND numbers in tricky ways!

Pattern 1: Alternating

Odd positions get numbers, even positions get shifted letters.

Example: HELLO

H (pos 1, odd) → 8
E (pos 2, even) → F (shift +1)
L (pos 3, odd) → 12
L (pos 4, even) → M (shift +1)
O (pos 5, odd) → 15

Code: 8F12M15

🎮 Practice Problem

Given: In a code:

• SUN = T30P
• SKY = T12Z

Find: The coding rule

Solution: Looking at SUN → T30P:

S → T (shift +1)
U → 30? Let's check: U is 21st letter
N → P (shift +2)

Wait, 30 doesn’t match 21… Let’s try:

• First letter: +1 shift
• Second letter: position + 9
• Third letter: +2 shift

Checking with SKY → T12Z:

S → T (shift +1) ✓
K = 11, 11 + 1 = 12 ✓
Y → Z (shift +1)...

Rule: First letter +1, middle letter = position + 1, last letter +1

💡 Mixed Coding Strategy

1. Separate letters and numbers first
2. Find pattern for each type
3. Check position (is it odd/even dependent?)
4. Verify with all given examples

4️⃣ Symbolic Coding

When Words Become Pictures

Instead of letters or numbers, we use symbols!

Common Symbol Patterns

🎮 Practice Problem

Given:

• APPLE = ★●●■△
• MANGO = ■★●●△

Find: How is GRAPE coded?

Solution: Looking at APPLE = ★●●■△:

A = ★ (first letter OR vowel start)
P = ● (consonant... wait)
P = ● (repeated)
L = ■
E = △ (last letter)

Let’s try another pattern with MANGO = ■★●●△:

M = ■ (consonant)
A = ★ (vowel)
N = ● (consonant)
G = ● (consonant)
O = △ (last letter)

New Theory:

• First letter = ★ or ■ based on vowel/consonant
• ● = middle letters
• △ = last letter

For GRAPE:

G = ■ (consonant, first)
R = ● (middle)
A = ● (middle)
P = ● (middle)
E = △ (last)

Answer: ■●●●△ ✅

🔣 Complex Symbol Rules

Sometimes symbols represent letter pairs or sounds:

Example: THINKING = @INK#

5️⃣ Sentence Coding

Cracking the Word Puzzle

Here, whole words are coded, not individual letters!

How It Works

You’re given multiple sentences with their codes. By comparing them, you find which word means what.

🎮 Practice Problem

Given:

1. “sky is blue” = “tic pac nic”
2. “grass is green” = “sic pac mic”
3. “blue grass” = “nic sic”

Find: What does “sky” mean?

Solution:

Step 1: Compare sentences

Sentence 1 & 2 share “is” and “pac”

"is" = "pac" ✓

Step 2: Use sentence 3

"blue grass" = "nic sic"
"blue" = "nic" OR "sic"
"grass" = "sic" OR "nic"

Step 3: Check with other sentences

From sentence 1: “sky is blue” = “tic pac nic”

• “is” = “pac” ✓
• So “sky” and “blue” = “tic” and “nic”

From sentence 2: “grass is green” = “sic pac mic”

• “is” = “pac” ✓
• So “grass” = “sic” (from sentence 3)
• So “green” = “mic”

Back to sentence 3: “blue grass” = “nic sic”

• “grass” = “sic” ✓
• So “blue” = “nic”

Therefore: “sky” = “tic”

Answer: tic ✅

📋 Sentence Coding Strategy

graph TD
    A["Find Common Words"] --> B["Match Common Codes"]
    B --> C["Eliminate Known Words"]
    C --> D["Solve Remaining"]
    D --> E["Verify Answer"]

1. Find overlapping words between sentences
2. Match them to overlapping codes
3. Eliminate solved words from equations
4. Solve the remaining unknowns
5. Verify your answer fits all sentences

🎯 Master Checklist

🧠 Memory Tricks

“LNMSS” - Remember the 5 types:

• Letter Coding
• Number Coding
• Mixed Coding
• Symbolic Coding
• Sentence Coding

🚀 You’re Now a Code Breaker!

Remember:

1. Stay calm - every code has a pattern
2. Write it down - don’t try to solve in your head
3. Check your work - verify with given examples
4. Practice daily - you’ll get faster!

“Every lock has a key. Every code has a pattern. You just need to find it!” 🔓

Quick Reference Card