Radix

In mathematical numeral systems, the radix or base is the number of unique digits, including the digit zero, used to represent numbers in a positional numeral system. For example, for the trezenal system (the system in this wiki) the radix is 10, because it uses the 10 digits from 0 through J. (the 10 digits are 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, $$X$$, $$B$$ , $$J$$ )

Commonly used numeral systems include: