Quinary is the base five numeral system. It uses the digits 0, 1, 2, 3, and 4 to represent any real number. This was a very common base among cultures because humans typically have five fingers on either hand.
In the Twentieth century only the East African Luo tribe of Kenya and the Yoruba of Nigeria were still using a base five system. However, the decimal system has prevailed in most areas and they, like most previously quinary-counting cultures, have converted.
The system of Roman numerals uses a quinary sub-base, (V, L, D) superimposed on a decimal base.