I represent 1,
V represents 5
X represent 10
L represents 50
C represents 100
D represents 500
M represents 1000
In order to read a roman number, we must remember the following rules; these rules help us to understand how to read Roman Numbers:
If the smaller sign is placed before the larger sign, it indicates that the smaller number is subtracted from the larger number.
On another hand if the smaller sign is placed after the larger sign, then it represents that the smaller number is added to the larger number.
Let us understand it with the help of the following example:
If we write IV, it shows that I is smaller than the sign of V (5). So we subtract 1 from 5 and os IV is the roman representation of (5 – 1) = 4.
On taking another example say VI, we observe that I is smaller than V and it is placed after V, so it is read as 5 + 1 = 6.
Now we take the example of IX, here I is smaller than x (10), so it is read as (10 – 1 = 9. But if the sign is represented as XII, here we find that the sign represents (10 + 1 + 1 = 12).
Three consecutive c, M, X and I can be written but we cannot write D, L or V more than one time, so if the roman form of the number is XXXI, it represents (10 + 10 + 10 + 1 = 31), but on another side if we have VVV or LLL then it is a wrong representation.