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 10
base 10 is a positional numeral system with ten as its base. It uses 10 different digits for representing numbers. The digits for base 10 could be 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9.