Here are the symbols used for roman numerals.

Roman numerals are read from left to right. If a symbol is succeeded by a larger symbol, the first symbol is subtracted from the total, otherwise it is added to the total. The last symbol is always added. A few examples:

Of course, some of the notations above are not standard, but one integer can have multiple roman numeral representations. For example, the standard way to denote 98 is XCVIII, but IIC makes just as much sense to me.

Here is a list of all the "standard" numbers using "reverse" notation: