What is in IIX Hindu Arabic?

Answer 1

IIX is not a valid Roman numeral. Roman numerals must be in descending order of value. Although II is valid symbol for the value 2, it cannot be followed by an X, because X is 10. And although IX is a valid symbol for 9, it cannot be preceded by an I, which is 1.

Taken literally, IIX would mean "one short of one short of ten", which would be 8, but VIII is the correct Roman numeral for eight (V is 5 so VIII is 5 + 1 + 1 + 1).

The accepted convention employs 13 symbols which can be added together, and all must be in descending order of value, using the largest possible values: I (1), IV (4), V (5), IX (9), X (10), XL (40), L (50), XC (90), C (100), CD (400), D (500), CM (900) and M (1000). The accepted convention also states that only I, X, C and M may be repeated, but no more than 3 times in succession.