A binary number is a way of representing values using only two symbols: 0 and 1. This system is the foundation of digital computing, as computers use binary to process and store data. Each digit in a binary number is called a bit, and a group of eight bits forms a byte, which can represent a wide range of information. In the binary system, each position in a number represents a power of 2. For example, the binary number 101 translates to the decimal number 5 because it is calculated as (1 × 2²) + (0 × 2¹) + (1 × 2⁰). This simple yet powerful system allows computers to perform complex calculations and operations efficiently.