text: All encoding on normal computers is binary at the lowest level, but octal and hexadecimal numbers are used used for shorthand.  Each octal digit is 3 bits, and each hex digit is 4 bits (2^3 = 8, 2^4 = 16).  Octal digits range from 0 to 7, and hex digits range from 0 to F (letters are used after 9).\n\nSpecial binary formats are used for signed and floating point numbers (i. e., 2's compliment form for signed numbers), but that seems beyond the scope of your question.