by Roman numerals are a number system that originated in ancient Rome. Instead of using the digits 0-9, they use combinations of these seven letters:
| Roman Numeral | Value |
|---|---|
| I | 1 |
| V | 5 |
| X | 10 |
| L | 50 |
| C | 100 |
| D | 500 |
| M | 1000 |
Basic Rules of Roman numerals
If a smaller numeral comes after a larger one, add it.
VI = 5 + 1 = 6
If a smaller numeral comes before a larger one, subtract it.
IV = 5 – 1 = 4
IX = 10 – 1 = 9
