# Roman Numerals

Roman numerals are essentially a decimal or "base ten" number system, but instead of place value notation (in which place-keeping zeros enable a digit to represent different powers of ten) the system uses a set of symbols with fixed values, including "built in" powers of ten.

| Symbol | Value |
| ------ | ----- |
| I | 1 |
| V | 5 |
| X | 10 |
| L | 50 |
| C | 100 |
| D | 500 |
| M | 1,000 |

The numerals for 4 (IV) and 9 (IX) are written using "subtractive notation", where the first symbol (I) is subtracted from the larger one (V, or X), thus avoiding the clumsier (IIII, and VIIII). Subtractive notation is also used for 40 (XL) and 90 (XC), as well as 400 (CD) and 900 (CM).

## Examples

* 39 = XXX + IX = XXXIX
* 246 = CC + XL + VI = CCXLVI
* 1,066 = M + LX + VI = MLXVI
* 1954 = M + CM + L + IV = MCMLIV