1-9 Ⅰ Ⅱ Ⅲ Ⅳ Ⅴ Ⅵ Ⅶ Ⅷ Ⅸ
10 Ⅹ
11-19在(1-9)这些数左面加X
20 XX
21-29在(1-9)这些数左面加XX
30 XXX
31-39在(1-9)这些数左面加XXX
40 XL
41-49在(1-9)这些数左面加XL
50 L
51-59在(1-9)这些数左面加L
60 LX
61-69在(1-9)这些数左面加LX
70 LXX
71-79在(1-9)这些数左面加LXX
80 LXXX
81-89在(1-9)这些数左面加LXXX
90 XC
91-99在(1-9)这些数左面加XC
100 C
如图所示: