How did Romans do (advanced) math using Roman numerals?
In: 590
Many comments mention that Roman numerals were not used for arithmetic. I cannot comment on that from a historical point of view, but I can say that addition and subtraction are easier with Roman numbers than with decimal notation (for those numbers representable in Roman numerals, of course). For instance let’s do CCXXXVII + CLVIII. You just throw everything together in order and then reduce:
CCCLXXXVVIIIII -> CCCLXXX(VV)(IIIII) = CCCLXXXXV = CCCXCV
Things like IX would have to be treated as single symbols in this process, or they can be expanded to VIIII before combining.
Subtraction is equally easy. To do CCXXXVII – CLVIII we remove C, so CXXXVII, then L so LXXXVII, then V so LXXXII, and finally we have three I where removing the first two gives us LXXX, and removing the last one gives us the final result LXXIX.
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