Numerical digit
numeric symbol used in combinations to represent numbers in positional numeral systems
Numerical digits are the number text characters used to show numerals. For example, the numeral "56" has two digits: 5 and 6. In the decimal system (which is base 10), each digit is how many of a certain power of 10 are needed to get the value. The rightmost, or units digit,[1] is for 10^0, the next digit is for 10^1, etc.
The numeral "56" means: 6*10^0 + 5*10^1 = 6*1 + 5*10 = 6 + 50.
The ten digits of the decimal system are: 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9. Some numeral systems need more than ten digits. For example, the hexadecimal numeral system uses 16 symbols to represent numericals : 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, and F.