Roman Numeral

I am always loss when using Roman Numeral
Dedicate to those who have same problem as me.. {^o^}

Arabic Roman
01 - I
02 - II
03 - III
04 - IV
05 - V
06 - VI
07 - VII
08 - VIII
09 - IX
10 - X
11 - XI
12 - XII
13 - XIII
14 - XIV
15 - XV
16 - XVI
17 - XVII
18 - XVIII
19 - XIX
20 - XX

Basic Numerical Symbols:
I - Represent Single digit
V - Represent 5
X - Represent 10
L - Represent 50
C - Represent 100
D - Represent 500
M - Represent 1000