nine million, one hundre thousand, four convert to roman numeral

It is quite a subject for large numbers written in Roman numerals.

The biggest single letter Roman numeral is M standing for one thousand.

Parentheses can be used to multiply numbers by 1000 times, so that (M) means one million. Others do it with an overline (a line over the letter) to achieve the same thing. Still others write vertical bars to do the same multiplication, |M| stands again for a million. Then came about some who would make combinations such as ((M)) to mean a thousand millions.

Based on this principle, 9 millions can be written as a 9 multiplied two times by one thousand, thus:
((I))((X))
One hundred thousand would simply be (C). So
Nine million one hundred thousand would be written as
((I)((X))(C), or in combination with overlines (hopefully correctly here):
(ī)(x̄)c̄.

The following references make interesting reading for interested readers:
http://en.wikipedia.org/wiki/Roman_numerals
http://www.web40571.clarahost.co.uk/roman/howtheywork.htm