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 in decimal. Read from right to left: positions represent
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.