Quinary (base-5 or pental) is a numeral system with five as the base. A possible origination of a quinary system is that there are five fingers on either hand.
base 11
base 11 is a positional numeral system with eleven as its base. It uses 11 different digits for representing numbers. The digits for base 11 could be 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, and a.