18 written in Roman numerals is XVIII.
Xviii
The Roman numeral XVIII represents the number 18
Do you mean 3-18-1992? If so then in today's notation of Roman numerals it is: III-XVIII-MCMXCI
18 - XVIII
The date 9-18-2008 in Roman numerals is IX-XVIII-MMVIII.
If you mean xviii then it is the equivalent of 18 otherwise it is an invalid arrangement of Roman numerals.
Xviii = 18 x = 10 v = 5 i = 1
xviii
XVIII/IX/MMX
XVIII
XVIII