Talen 1620 till 1626 i romerska siffror
I högerkolumnen visas hur varje romersk siffra bidrar till att man hamnar vid rätt tal.
| 1620 | = | MDCXX | = | 1000 + 500 + 100 + 10 + 10 |
| 1621 | = | MDCXXI | = | 1000 + 500 + 100 + 10 + 10 + 1 |
| 1622 | = | MDCXXII | = | 1000 + 500 + 100 + 10 + 10 + 1 + 1 |
| 1623 | = | MDCXXIII | = | 1000 + 500 + 100 + 10 + 10 + 1 + 1 + 1 |
| 1624 | = | MDCXXIV | = | 1000 + 500 + 100 + 10 + 10 + 5 − 1 |
| 1625 | = | MDCXXV | = | 1000 + 500 + 100 + 10 + 10 + 5 |
| 1626 | = | MDCXXVI | = | 1000 + 500 + 100 + 10 + 10 + 5 + 1 |