Roman numerals get nine by putting I, which equals 1, before X, which equals 10, to essentially indicated 10-1=9. For comparison, when I appears after X, as in XI, that indicates 10 + 1 ...

Factor XI deficiency is a rare, inherited bleeding disorder. XI means “eleven” in Roman numerals. Factor XI deficiency is sometimes called hemophilia C and is a relatively mild form of hemophilia.

So, you're a little bit confused about Roman numerals. Don't worry. There is an expert here to help you understand this Super Bowl nonsense. Roman numerals can be summarized ... Roman numerals are ...