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.