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# Roman Numbers

Roman number system is named so because it was introduced in Rome. The Romans discovered a new and compact way of writing numbers. They used Latin language as well as English language letters to write numbers in an easier way. Initially, they started using Roman numbers for the names of emperors and their sons, such as, George IV. Roman numbers are still widely used in real life.

Symbols used in Roman number system are as follows:

• I : Used for "1".
• V: Used for "5".
• X : Used for "10".
• L: Used for "50".
• C: Used for "100".
• D: Used for "500".
• M: Used for "1000".

Rules for Writing Roman Numbers

There are few rules which are to be followed while writing Roman numbers:

• If a smaller number comes before a larger one, then smaller is subtracted from larger. For example: IV means 5 - 1 = 4.
• If a larger number comes before smaller one, then both are added. For example: VI means 5 + 1 = 6.
• A same symbol can not be used more than thrice in a row. For example: For 3, write III. But for 4, do not write IIII.
• The numbers much bigger than 1000 are written by placing a "bar" over the symbols. This "bar" means "times 1000". For example: $\bar{V}$ means 5 times 1000 or 5000 and $\bar{X}$ means 10 times 1000 or 10,000.

Let us have a look at an example of Roman numbers.

Example: Write following numbers in Roman number system:
503, 900 and 1454.

Solution:
(1)  503 can be written as 500 + 3.
500 = D
3 = III
For addition, write larger number before.
Therefore, 503 = DIII.

(2) 900 can be written as 1000 - 100
1000 = M
100 = C
For subtraction, smaller number comes before.
Therefore, 900 = CM.

(3) 1454
1454 can be written as 1000 + 400 + 50 + 4
1000 = M
400 = 500 - 100 = CD
50 = L
4 = 5 - 1 = IV
Therefore, 1454 = MCDLIV

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