A Singular Destiny
A numbering system similar to roman numerals was used by whoever built the ancient power generation facility beneath Downwater, and the door in the side of the Clock of Kala. The symbols/digits used:
Numbers are read outwards from the largest digit. A smaller digit to the left of a larger one subtracts from it; to the right, adds. The same digit repeated is additive.
512 – (128+32) + (8+4+1+1) = 366