Hi!
In roman numerals, x means 10, and i means one. If you put a smaller number before a larger one, like iv (v = 5), then you get what v - i is, or 4.
Therefore, i x ii means, either 9 + 1 + 1 written in an odd way, to make 11, or just 9-1-1 as three digits.
Hope this helped!