The numbers 665 to 671 in roman numerals
The right column shows how each roman numeral adds up to the total.
| 665 | = | DCLXV | = | 500 + 100 + 50 + 10 + 5 |
| 666 | = | DCLXVI | = | 500 + 100 + 50 + 10 + 5 + 1 |
| 667 | = | DCLXVII | = | 500 + 100 + 50 + 10 + 5 + 1 + 1 |
| 668 | = | DCLXVIII | = | 500 + 100 + 50 + 10 + 5 + 1 + 1 + 1 |
| 669 | = | DCLXIX | = | 500 + 100 + 50 + 10 + 10 − 1 |
| 670 | = | DCLXX | = | 500 + 100 + 50 + 10 + 10 |
| 671 | = | DCLXXI | = | 500 + 100 + 50 + 10 + 10 + 1 |