You could certainly write numbers above 9 as their base-10 representation. For example, 12. That number can be represented in both Kaktovik numerals and arabic.

You could certainly write numbers above 9 as their base-10 representation. For example, 12. That number can be represented in both Kaktovik numerals and arabic. But you end up with an extra digit in arabic numerals, because you're supposed to carry the 1 once you reach 10. Instead, we represent hexadecimal (base-16) in programming as 0-9 AND a-f, for example, A is 10, B is 11, C is the same as saying 12. If you have multiple digits, like A4C in hex, it gets more complicated to figure out what number you're talking about in base-10. A is 10, 4 is 4, C is 12. To convert base-10 number you need to do this equation: (10 * 16 * 16) + (4 * 16) + (12) = 2636