| 罗马数字 | 数值 |
| I | 1 |
| II | 2 |
| III | 3 |
| IV | 4 |
| V | 5 |
| VI | 6 |
| VII | 7 |
| VIII | 8 |
| IX | 9 |
| X | 10 |
| XI | 11 |
| XII | 12 |
| XIII | 13 |
| XIV | 14 |
| XV | 15 |
| XVI | 16 |
| XVII | 17 |
| XVIII | 18 |
| XIX | 19 |
| XX | 20 |
| XXX | 30 |
| XL | 40 |
| L | 50 |
| LX | 60 |
| LXX | 70 |
| LXXX | 80 |
| XC | 90 |
| XCIX | 99 |
| C | 100 |
| CI | 101 |
| CII | 102 |
| CXCIX | 199 |
| CC | 200 |
| CCC | 300 |
| CD | 400 |
| D | 500 |
| DCCC | 800 |
| CM | 900 |
| M | 1,000 |
| MCD | 1,400 |
| MCDXXXVII | 1,437 |
| MD | 1,500 |
| MDCCC | 1,800 |
| MDCCCLXXX | 1,880 |
| MCM | 1,900 |
| MM | 2,000 |
| MMI | 2,001 |
| MMC | 2,100 |
| MMCC | 2,200 |
| MMCM | 2,900 |
| MMM | 3,000 |
| MMMCCCXXXIII | 3,333 |
| MMMDCCCLXXXVIII | 3,888 |
参考：
所以 XXII.XI.MMXII 就是 2012.11.22