What are the rules for writing roman numbers?

Answer 1

The basic and most common Roman numbers are as follows:

I = 1

V = 5

X = 10

L = 50

C = 100

D = 500

M = 1000

The rules for using them are fairly simple, using specific placement of the numbers to indicate addition or subtraction to the base number. For the most part, you add the values of the letters until placement tells you to do otherwise. If you need to add three, or less, to the base number, then place the added numbers to the right of the base number. For example, the number '8' would be written VIII (5 + 3) and the number '13' would be written XIII (10 + 3). If you need to add four to the base number, then you express this by subtracting one from the base number, and placing the number to the left of the base number. For example, the number '4' is written IV (5 - 1), and the number '9' is written IX (10 - 1). For more elaborate examples, the year '2010' would be written MMX (1000 + 1000 + 10), and the year '1964' would be written MCMLXIV (1000 - 100 + 1000 + 50 + 10 - 1 + 5).