@Almondee I'll start again with some examples.
binary contains the digits 0 and 1. To write the decimal number 2 in binary it is "10". So if we write base 2 in binary, we would call it "base 10".
Hex contains the digits 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, F. To write the decimal number 16 in hex it is "10". So if we write base 16 in hex, we would call it "base 10".
in this way, all systems are base 10.