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.
base 6
base 6 is a positional numeral system with six as its base. It uses 6 different digits for representing numbers. The digits for base 6 could be 0, 1, 2, 3, 4, and 5.