The vigesimal or base 20 numeral system is based on twenty (in the same way in which the decimal numeral system is based on ten).
base 8
base 8 is a positional numeral system with eight as its base. It uses 8 different digits for representing numbers. The digits for base 8 could be 0, 1, 2, 3, 4, 5, 6, and 7.