Roman numerals are a number system developed in ancient Rome where letters represent numbers. The modern use of Roman numerals involves the letters I, V, X, L, C, D, and M.

The set of basic symbols of the Roman system of writing numerals :
I = 1 (one)
V = 5 (five)
X = 10 (ten)
L = 50 (fifty)
C = 100 (one hundred)
D = 500 (five hundred)
M = 1,000 (one thousand)
|V| = 5,000 (five thousand)
|X| = 10,000 (ten thousand)
|L| = 50,000 (fifty thousand)
|C| = 100,000 (one hundred thousand)
|D| = 500,000 (five hundred thousand)
|M| = 1,000,000 (one million)