Romannumeral

A Roman numeral is a numeral system originating in ancient Rome and used for representing integers by combining letters from the Latin alphabet. The standard symbols are I (1), V (5), X (10), L (50), C (100), D (500), and M (1000).

Numbers are formed by reading from left to right. When a symbol of smaller value precedes a larger value, it is subtracted; otherwise its value is added. For example, VI equals 6, and XIV equals 14. Subtractive notation is used for certain values: IV (4), IX (9), XL (40), XC (90), CD (400), and CM (900). Subtraction is typically allowed only for I from V and X, X from L and C, and C from D and M; V, L, and D are not subtracted. A symbol is generally not repeated more than three times in a row. Larger numbers are written by repeating M as needed for thousands. There is no symbol for zero. For very large values, overlines (vincula) or multiple Ms are used to indicate multiplication by 1,000.

Historically, Roman numerals were used across the Roman world and continued into medieval Europe for inscriptions, commerce, and daily notation. They persist in certain contexts today, such as clock faces, chapter and section numbering, monarchial regnal numbers, and event dating.

In modern text, Roman numerals can be represented using standard Unicode characters for uppercase and lowercase forms, and conversion between Roman and Arabic numerals can be performed algorithmically. While not suited for routine arithmetic, they remain a familiar method of enumerating items and marking tradition.