First egregious Wrongness in _1491_
Jun. 21st, 2022 05:22 pm![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
walkitout“Without a positional notation system, arithmetic is tedious and hard, as schoolchildren learn when teachers force them to multiply or subtract with Roman numerals.”
Oh dear.
OK, first off, addition and subtraction are dead easy with roman numerals. Normalize to additive only. For addition, concatenate and sort. For subtraction, mark off matching ones, and then deal with the remainder in the obvious way.
Multiplication and division are more complicated, but there is a well-defined procedure for multiplication.
https://math.stackexchange.com/questions/1530406/how-to-multiply-roman-numerals
Here’s a bit about division:
https://history.stackexchange.com/questions/41435/how-did-the-romans-do-division
But really, the relevant answer is not how you _write_ the calculations. Writing wasn’t a cheap thing to do then; they used abacus.
Oh dear.
OK, first off, addition and subtraction are dead easy with roman numerals. Normalize to additive only. For addition, concatenate and sort. For subtraction, mark off matching ones, and then deal with the remainder in the obvious way.
Multiplication and division are more complicated, but there is a well-defined procedure for multiplication.
https://math.stackexchange.com/questions/1530406/how-to-multiply-roman-numerals
Here’s a bit about division:
https://history.stackexchange.com/questions/41435/how-did-the-romans-do-division
But really, the relevant answer is not how you _write_ the calculations. Writing wasn’t a cheap thing to do then; they used abacus.