Base-16 (also known as hexadecimal) number system uses 16 symbols to code information. Most commonly, these symbols are, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, and 'A to F' (or alternatively 'a to f').
Base-24 number system uses 24 symbols to code information. Most commonly, these symbols are, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, and 'A to N' (or alternatively 'a to n').