How did the Romans pronounce roman numerals?

Question

As I understand it, their notation (subtractive notation?) is quite hard and tedious to work with even for its natives. In fact, many numbers are themselves math problems.

How did they speak of their arcane numerology to one another? They presumably did not speak in positional notation—if math truly is easier that way—or else they'd have adopted it in writing as well. Further, they surely did not simply speak the symbols aloud one at a time. We do not pronounce "1300" as "one, three, zero, zero." Instead, we say "one-thousand and three-hundred." Or alternatively, "thirteen-hundred."

So, how did Romans pronounce, say, the number 43? Surely it was not some equivalent to "ten, one, one, one, fifty"?

Answer 1

As Eleshar pointed out in a comment, the Roman numeral system is more flexible than many sources let you believe. However, the rigid system usually taught in schools actually does have a kind of positional notation.

For example, 43 is XLIII, or 40+3 is XL+III. The decimal in the first position is fully expressed before moving to the next one. For example, 1994 = 1000+900+90+4 = M+CM+XC+IV = MCMXCIV. Admittedly, this is not fully positional notation since a varying number of symbols (from zero to four) is used to express each decimal. However, after playing with Roman numerals for a while you will learn to recognize quickly where the decimal changes. In reality the Romans used many variants, and not all of them had this positional property.

The Roman words for numbers were no less sophisticated than the modern English ones. Actually quite the opposite: Latin had (and still has!) four kinds of numerals for different uses whereas English has two or three. For number one, the words are unus, primus, semel, and singuli. In English these are "one", "first", "once" and "one at a time". (Not all numbers have the third version in English; you have to say "ten times".) Observe also that the Roman numeral words do follow the decimal system. Roman oral numerals were hardly "arcane numerology" — or if they were, so are the English ones.

The Roman symbols for numbers were clumsier than our modern ones, but they have little to do with how the numbers were pronounced. It is worth observing that the Romans did not have separate symbols for numbers like we do, but they used letters from their alphabet. (For large numbers they used some additional symbols, but let me not digress.) Had they had separate symbols, I believe they would have come up with a simpler system.

Answer 2

43 in Latin is quadraginta et tres. There is no relation between the names of numbers and the numeric notation system, in which it would be XLIII. The closest thing to what you seem to be imagining is that they called 19 undeviginti, "one from twenty". But then they called 18 duodeviginti. "two from twenty", even though they didn't write it IIXX.

Wiktionary for Roman numerals.