Talen 284 till 290 i romerska siffror
I högerkolumnen visas hur varje romersk siffra bidrar till att man hamnar vid rätt tal.
| 284 | = | CCLXXXIV | = | 100 + 100 + 50 + 10 + 10 + 10 + 5 − 1 |
| 285 | = | CCLXXXV | = | 100 + 100 + 50 + 10 + 10 + 10 + 5 |
| 286 | = | CCLXXXVI | = | 100 + 100 + 50 + 10 + 10 + 10 + 5 + 1 |
| 287 | = | CCLXXXVII | = | 100 + 100 + 50 + 10 + 10 + 10 + 5 + 1 + 1 |
| 288 | = | CCLXXXVIII | = | 100 + 100 + 50 + 10 + 10 + 10 + 5 + 1 + 1 + 1 |
| 289 | = | CCLXXXIX | = | 100 + 100 + 50 + 10 + 10 + 10 + 10 − 1 |
| 290 | = | CCXC | = | 100 + 100 + 100 − 10 |