The numbers 13 to 19 in roman numerals
The right column shows how each roman numeral adds up to the total.
| 13 | = | XIII | = | 10 + 1 + 1 + 1 |
| 14 | = | XIV | = | 10 + 5 − 1 |
| 15 | = | XV | = | 10 + 5 |
| 16 | = | XVI | = | 10 + 5 + 1 |
| 17 | = | XVII | = | 10 + 5 + 1 + 1 |
| 18 | = | XVIII | = | 10 + 5 + 1 + 1 + 1 |
| 19 | = | XIX | = | 10 + 10 − 1 |