Octal uses 8 digits (0-7) and is primarily used in some traditional computer systems and Unix file permissions.

• Uses digits 0-7
• Widely used in early computer systems
• Each octal digit represents 3 binary bits
• Often uses '0' prefix, such as '0o755'

Hexadecimal uses 16 symbols: 0-9 and A-F (or a-f), widely used in programming and computer science.

• Uses digits 0-9 and letters A-F (or a-f)
• Commonly used for memory addresses and color values
• Each hex digit represents 4 binary bits
• Often uses '0x' prefix, such as '0x1A3F'