When we need to write the date in the form of roman numerals, we need to know the roman representation of the numbers.

In this unit, we will study how to write dates in roman numerals. For this, we must first learn the basic symbols which we use to represent the decimal numbers.

- ‘I’ is used for 1
- ‘V’ is used for 5
- ‘X’ is used for 10
- ‘L’ is used for 50
- 'C’ is used for 100
- ‘D’ is used for 500
- ‘M’ is used for 1000.

We must remember some of the basic rules of writing the roman numerals. Here, we say that the symbol X, I, C and M can be written at the most three times together.

If the symbol of smaller number appears before the larger symbol, it indicates that the smaller number is to be subtracted from the larger one. On the other hand, if the smaller symbol appears after the larger symbol, then the two numbers are to be added up. So, we say that IX represents 10 - 1 = 9 and XI represents 11.

For example, if we say that today’s date is 13

^{th}May 2012, then to represent this date, we will write it as XII - V - MMXII.

Here, we find that XII is used to represent 10 + 1 + 1 = 12, which is the date.

Then, ‘V’ represents 5, which represents the fifth month i.e. may.

We have MMXII to represent the year i.e. 1000 + 1000 + 10 + 1 + 1 = 2012.