I've always learned roman numerals using the following method.
Regardless of the ordinal position, 1 thru 9 in that position is
represented by the same amount of characters. Every fifth element
changes the code. This code is introduced one value earlier using a
subractive method. i.e. Four(IV) being one(I) less than five(V):
4: IV (the 'one' preceding the 'five' symbol is subtractive)
9: IX (see number four)
That particular roman numeral calculator probably substitutes
characters with a face value and adds it all up. That's why MDCCCCI
calculated to 1901
--- In email@example.com, "Evan" <evan947@y...> wrote:
> Now, I **REALLY** like calling our museum MCMI, but the Roman
> site also will accept MDCCCCI and other combinations as 1901. LOL,
> anyone here a math historian? Which is the "proper" format?