Binary

Counting using only two digits — 0 and 1. It's how computers represent everything internally.

A positional number system with base 2. Each column is a power of two, so 1010 = 8 + 2 = 10. All digital data, from numbers to images, ultimately reduces to binary.

Base-2 positional notation. Closed under arithmetic with carry propagation. Direct correspondence to two-state digital logic makes it the natural representation for hardware. Two's complement extends it to signed integers without a separate sign bit.