Roman numerals are entered using capital letters of the Latin alphabet, at least I do this, but in fact the ancient Romans did the same. One is a big I (I), five is V, ten is X, 50 is L, etc. More details can be found in the wiki (https://ru.wikipedia.org/wiki/%D0%A0%D0%B8%D0%BC%D1%81%D0%BA%D0%B8%D0%B5_%D1%86 % D0% B8% D1% 84% D1% 80% D1% 8B)
Translate into English and write like I - 1, V - 5, etc. Large letters in English. And everything will work out. I - 1, II - 2, III, IV, V, VI, VII, VIII, IX, X.