M(V)CDX = 4,410? How to convert the Roman numeral? Is it valid or not?. Numbers such as I, VI and IX are called Roman numbers (or Roman numerals). Roman numerals are represented by a string consisting of characters "I", "V", "X", "L", "C", "D" and "M". Improve your math knowledge with free questions in "Roman numerals I, V, X, L, C, D, M" and thousands of other math skills. The IVXLCDM problem is an analogous problem, where Roman numerals are used. Read on to learn about Roman Numerals or go straight to the Roman Numeral Conversion Tool.