Binary Fundamentals

Binary (base-2) uses only two digits: 0 and 1. Each position represents a power of 2 instead of 10.

The binary number 1011 means $1 \times 2^3 + 0 \times 2^2 + 1 \times 2^1 + 1 \times 2^0 = 8 + 0 + 2 + 1 = 11$ in decimal. Read from right to left: positions represent $1, 2, 4, 8, 16, 32, 64, 128...$

Every 1 in a binary number "turns on" that power of 2. Every 0 "turns off" that power. Add up the turned-on powers and you get the decimal value. This is how computers represent all data.