Computers use the binary number system (base-2, digits 0/1) as their fundamental representation, alongside other systems used by programmers: decimal (base-10), octal (base-8), and hexadecimal (base-16, digits 0-9 and A-F).

• ›Binary's adoption reflects hardware reality: digital circuits naturally represent TWO stable states (ON/OFF, high/low voltage), making base-2 the NATURAL hardware-level representation
• ›Hexadecimal is commonly used by programmers as a more COMPACT, human-readable shorthand for binary (each hex digit represents exactly 4 binary bits), NOT because hardware uses it directly