The numbers 400 to 406 in roman numerals
The right column shows how each roman numeral adds up to the total.
| 400 | = | CD | = | 500 − 100 |
| 401 | = | CDI | = | 500 − 100 + 1 |
| 402 | = | CDII | = | 500 − 100 + 1 + 1 |
| 403 | = | CDIII | = | 500 − 100 + 1 + 1 + 1 |
| 404 | = | CDIV | = | 500 − 100 + 5 − 1 |
| 405 | = | CDV | = | 500 − 100 + 5 |
| 406 | = | CDVI | = | 500 − 100 + 5 + 1 |