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Q: How did the ancients calculate with Roman numerals?

A: They didn’t, according to USC mathematician Solomon W. Golomb. The Romans had Greek household slaves or retainers who did all their calculating for them using a Greek numeric system. That system was not unlike the currently used arabic system, except that there was no symbol for zero. Multiplication was easy in this system, Golomb said, but “long division was something to be avoided at all costs.”

Arabic numerals were introduced into Europe at the beginning of the 13th Century by the Italian mathematician Fibonacci and immediately came into wide use among those who had to perform calculations. Thus, although bankers kept their books in Roman numerals until well into the 1600s, they performed all their calculations with arabic numerals.

Systems have been developed for calculating with Roman numerals, but they are more like parlor games than practical applications, Golomb said.