What is the longest and shortest way of notating 993 in Roman numerals?

Answer 1

The modern way of expressing 993 in Roman numerals is now CMXCIII but the ancient Romans would have most probably calculated the equivalent of 993 on an abacus counting device as DCCCCLXXXXIII and then by placing X to both sides of it abridged it to XMIII meaning (-10+1003 = 993) in written format as we still do today as for example instead of writing out VIIII for 9 we abridge it to IX meaning (-1+10 = 9) in written format.

Note that in fact the sum of CM+XC+III equals XMIII which is equivalent to DCCCCLXXXXIII