Well, here is a quick overview, so you don't have to write out all of them.1 - I5 - V10 - X50 - L100 - C500 - D1000 - MThey go from highest to lowest when written, and they are added up as you go...
1 = I 5 = V 10 = X 50 = L 100 = C 500 = D 1000 = M All other numbers are made up of a combination of these letters, with no more than three identical letters permitted consecutively. CCC = 300, but...