The duodecimal system (also known as base 12 or dozenal) is a positional notation numeral system using twelve as its base.
base 15
base 15 is a positional numeral system with fifteen as its base. It uses 15 different digits for representing numbers. The digits for base 15 could be 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, a, b, c, d, and e.