Quinary (Positional systems), numerals
Quinary (base-5) is a numeral system with five as the base. This originates from the five fingers on either hand: the most primitive numeral system. In the quinary place system, five numerals from 0 to 4, are used to represent any real number. According to this method, five is written as 10, twenty-five is written as 100 and sixty is written as 220.