All four number bases, in sync
Computers count in different bases: binary (base 2) is the raw machine language, hexadecimal (base 16) compresses binary into a compact form used for colors and memory addresses, octal (base 8) appears in file permissions, and decimal (base 10) is what humans use. Type a number in any field and the other three update instantly.
For example, decimal 255 = hex FF = binary 11111111 = octal 377 — the classic maximum of a single byte.