The numbers 661 to 667 in roman numerals
The right column shows how each roman numeral adds up to the total.
| 661 | = | DCLXI | = | 500 + 100 + 50 + 10 + 1 |
| 662 | = | DCLXII | = | 500 + 100 + 50 + 10 + 1 + 1 |
| 663 | = | DCLXIII | = | 500 + 100 + 50 + 10 + 1 + 1 + 1 |
| 664 | = | DCLXIV | = | 500 + 100 + 50 + 10 + 5 − 1 |
| 665 | = | DCLXV | = | 500 + 100 + 50 + 10 + 5 |
| 666 | = | DCLXVI | = | 500 + 100 + 50 + 10 + 5 + 1 |
| 667 | = | DCLXVII | = | 500 + 100 + 50 + 10 + 5 + 1 + 1 |