IVDCCCXVI

IVDCCCXVI is a string of characters that appears to be written using Roman numerals: I, V, D, C, C, C, X, V, I. It is not a standard, canonical Roman numeral form.

If interpreted by the usual additive-subtractive rules, the value is 810. In step terms: I before V subtracts 1; V before D subtracts 5; D adds 500; the three Cs add 100 each (300); X adds 10; V adds 5; I adds 1. Sum: -1 - 5 + 500 + 100 + 100 + 100 + 10 + 5 + 1 = 810.

Because subtractive notation is misapplied here (IV preceding D is nonstandard), the string is noncanonical; the standard way to write 810 is DCCCX.

In modern use, such combinations are generally avoided; the string is mainly of interest to illustrate quirks of Roman numerals. There are no known historical uses associated with "IVDCCCXVI" as a number; it may appear in puzzles or as a random example.