18
810 (DCCCX is already in Roman numbers; 810 is in Arabic)
17% of 810= 17% * 810= 0.17 * 810= 137.7
5% of 810= 5% * 810= 0.05 * 810= 40.5
810
800
810
810
810
810/2 = 405 810/3 = 270 * 810/4 = 202.5 810/5 = 162 810/6 = 135 810/9 = 90 810/10 = 81 so 810 is divisible by 2 3 5 6 9 10 but not by 4
810
810