base 5 is a positional numeral system with five as its base. It uses 5 different digits for representing numbers. The digits for base 5 could be 0, 1, 2, 3, and 4.
base 2
base 2 is a positional numeral system with two as its base. It uses 2 different digits for representing numbers. The digits for base 2 could be 0, and 1.