Quaternary is the base-4 numeral system. It uses the digits 0, 1, 2 and 3 to represent any real number.
base 16
base 16 is a positional numeral system with sixteen as its base. It uses 16 different digits for representing numbers. The digits for base 16 could be 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, a, b, c, d, e, and f.