The binary number system is a base-2 system, meaning it only uses two digits: 0 and 1. This is the fundamental language of computers.

Unlike our everyday decimal system (base-10), which uses ten digits (0-9), binary represents all numbers using combinations of these two digits.

Each digit in a binary number is called a bit (short for binary digit).

Each position in a binary number has a value that is a power of 2. You start from the rightmost digit, which represents 2⁰ (which is 1).

Moving left, the positions represent 2¹, 2², 2³, and so on (2, 4, 8, 16...).

To convert binary to decimal, you add up the values of the positions that contain a '1'.

The most common method is repeated division by 2. You divide your decimal number by 2 and write down the remainder (which will always be 0 or 1).

You continue dividing the result (the quotient) by 2 and recording the remainder each time, until the quotient is 0.

The binary number is the sequence of remainders read from the bottom up.

Computers use binary because it's a reliable way to represent the two states of an electrical switch: On or Off.

A '1' can represent a switch being 'On' (current flowing), and a '0' can represent it being 'Off' (no current).

This simple, two-state system is much easier for electronic circuits to handle than a ten-state system like decimal, making it incredibly fast and efficient for computation.

All digital information is stored and processed in binary.

Text: Each character is assigned a unique binary code (like in ASCII or Unicode). The letter 'A' is 01000001.

Images: An image is a grid of pixels, and the color of each pixel is represented by binary numbers (e.g., for its Red, Green, and Blue values).

Sound: Audio is sampled at high speed, and the value of each sample is stored as a binary number.