tell me how to write in roman number!?

I = 1

V = 5

X = 10

L = 50

C = 100

D = 500

M = 1000

Combine them...

III = 3 (1 + 1 + 1)

XVI = 16 (10 + 5 + 1)

If the number is before another, it's that much less

IV = 4 (1 less than 5)

VI = 6 (1 more than 5)

XC = 90 (10 less than 100)

CX = 110 (10 more than 100)

MMIX = 2009 (1000 + 1000 + 9 (1 less than 10))

Remember..

I=1, V=5, X=10, L=50, C=100, D=500, M=1000 are the only Roman Numbers we have.

Except 'M' all other Roman Numbers are to be return max thrice.

Ex: Four Hundred is to be return as CD but not CCCC.

If there is a smaller number to the left of a larger number, then the smaller number is to be substracted from larger number.

Ex: as told above, 400=CD since C=100, D=500 => 400=500-100

I=1, II=2 III=3 but IV=4 but not IIII

And 40 is not XXXX but it is XL

in the same way, if you analyze and practice for some time , you will know how to write a Roman Number..

I = 1

V = 5

X = 10

L = 50

C = 100

D = 500

M = 1000

Combine them...

III = 3 (1 + 1 + 1)

XVI = 16 (10 + 5 + 1)

If the number is before another, it's that much less

IV = 4 (1 less than 5)

VI = 6 (1 more than 5)

XC = 90 (10 less than 100)

CX = 110 (10 more than 100)

MMIX = 2009 (1000 + 1000 + 9 (1 less than 10))

The Roman numerals, with their values, are:

I = 1

V = 5

X = 10

L = 50

C = 100

D = 500

M = 1000

Numbers are made by combing groups of numerals with the following rules:

1 - No more than three of any particular numeral can appear together in a number. The only exception to this is M. While it's technically correct to put a bar over V through M to indicate numbers 5000 through 1,000,000 or to put parenthesis around the portion of the number that is to be multiplied by 1000, most Romans just wrote out all the Ms. (e.g. 5000 was usually written as MMMMM and not (V) or V with a bar over it)

2 - Where four numerals are required, you should instead write the next larger numeral preceded immediately by a numeral to indicate subtraction. (e.g. 4 should be written as "IV" not "IIII").

3 - Numerals, except where required by rule 2, should be written in descending order of magnitude from left to right. (e.g. 114 should be written as CXIV not as IVCX or CIVX).