Is it possible to write the number zero (0) in Roman numerals, and if so, how?

And where is the sign for the Roman zero? There is none, because there is no need for zero.

http://www.mathematische-basteleien.de/romannumerals.htm

Roman numerals are not positional, so there is no actual need for a zero. In the system we use at present, we have 10 digits whose value at any time depends on the position they are in in the number - 1046 is quite different to 6401. In Roman numerals, MXXXXVI is the same as IXXXXMV. The first one is the usual way of writing it. However, in later times of Rome, a slightly positional system was used. MXXXXVI would be written MXLVI which can't be rearranged. Whichever way you write the Roman numbers, addition and subtraction are not too hard - you just collect like terms and count them up or cancel them out (making allowance for things like XL, of course. Division and multiplication are far harder. Decimals are impossible, and fractions difficult. Without the 0, a true positional system is not possible. You need to know that there aren't any hundreds in 1046. In the Roman system, you just didn't worry.