What are the two methods of addition that the Romans would have used to add together the equivalent of 403 99 49 and 449 showing details of your work in your answers?

Answer 1

Today we would convert these numbers into Roman numerals as CDIII, XCIX XLIX and CDXLIX respectively which makes addition of them almost impossible.

However, notwithstanding the above the Romans probably wrote out the equivalent of 403, 99, 49 and 449 in a simplified format as CDIII, IC, IL and ILD respectively which makes addition of them straightforward as follows:-

CDIII+IC = DII (403+99 = 502)

DII+IL = DLI (502+49 = 551)

DLI+ILD = M (551+449 = 1000)

Alternatively the Romans could have used an abacus counting device to add together these numerals in their expanded format:-

CCCCIII+LXXXXVIIII = DII (403+99 = 502)

DII+XXXXVIIII = DLI (502+49 = 551)

DLI+CCCCXXXXVIIII = M (551+449 = 1000)

Roman numerals: M=1000, D=500, C=100, L=50, X=10, V=5 and I=1