[pushedx]

10 * 10 * 10 * 10 in base 12 is 10000.

<12> * <12> * <12> * <12> in base 12 is 10000

Assuming that you mean the decimal number "12" and not the number 12 in base 12 which is the decimal number 14.

In base 12 the number 12 is written "10"