🌟 Chapter 2: Number System - Notes 🌟

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💡 What is a Number System?:-

A number system is a way to represent numbers using a set of symbols.
Just like we use 0-9 in everyday life, computers use their own unique systems to understand and process data!

Types of Number Systems:

Decimal

10

0 to 9

Humans (us 😌)

Binary

2

0, 1

Computers 🖥️

Octal

8

0 to 7

Shorter binary 😎

Hexadecimal

16

0 to 9 + A to F (A=10...F=15)

Programmers 👩‍💻✨

🔁 Base = Total Number of Digits

E.g.

Base 10 → 10 digits → 0-9 Base 2 → 2 digits → 0 & 1 Base 16 → 16 symbols → 0-9 + A-F

So if a number is written in base 2, it's binary.
If it's in base 16, it's hexadecimal.

🧠 Positional Number System:-

Each digit's value depends on:

The digit itself Its position in the number The base of the number system

Example (Decimal):

356 =
(3 × 10²) + (5 × 10¹) + (6 × 10⁰)
= 300 + 50 + 6 = 356

Same thing works in binary too, just with base 2:
1011₂ =
(1 × 2³) + (0 × 2²) + (1 × 2¹) + (1 × 2⁰)
= 8 + 0 + 2 + 1 = 11

🛠️ Conversion Basics:

We'll get deeper later, but here's the TL; DR:

Method

Decimal → Binary

Divide by 2, write remainders upwards

Binary → Decimal

Multiply bits by 2ⁿ powers and add

Decimal → Octal

Divide by 8

Decimal → Hex

Divide by 16

Binary ↔ Octal

Group 3 bits

Binary ↔ Hex

Group 4 bits

(I'll teach you all the tricks later, don't worry 🤭)

📦 Why Do We Need Different Number Systems?:-

Because computers speak in binary (only 0s and 1s), and humans speak in decimal.
So we need to convert between systems to make sense of things.

✨ Hex and Octal are used to shorten long binary numbers without losing meaning!

💖 Keywords to Remember:

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