Roman Numerals

Roman numerals are a numeral system that originated in ancient Rome and remained the usual way of writing numbers throughout Europe well into the Late Middle Ages. The system uses combinations of letters from the Latin alphabet to represent values.

Roman numerals use both additive and subtractive notation. In additive notation, values are added together (e.g., III = 3). In subtractive notation, a smaller numeral is placed before a larger one to subtract its value (e.g., IV = 4, meaning 5 - 1). The system is not positional like modern Arabic numerals, but rather uses a combination of symbols with fixed values.

Key Features:

• Uses 7 basic symbols: I, V, X, L, C, D, M representing 1, 5, 10, 50, 100, 500, and 1000.
• Additive notation: symbols are added together (e.g., II = 2, VII = 7).
• Subtractive notation: smaller symbol before larger subtracts (e.g., IV = 4, IX = 9, XL = 40, XC = 90).
• No symbol for zero - the concept of zero was not used in Roman numerals.
• Still used today for numbering chapters, book volumes, movie sequels, clock faces, and other contexts.
• Larger numbers use an overline (vinculum) to multiply by 1000 (e.g., V̅ = 5000, X̅ = 10000).

Formation Rules:

• Symbols are written from left to right, largest to smallest.
• When a smaller symbol appears before a larger one, it is subtracted.
• Only I, X, and C can be used for subtraction (before V, X, L, C, D, M respectively).
• Only one smaller symbol can be placed before a larger one for subtraction.
• No more than three identical symbols can be used consecutively.

Further Reading:

• Roman Numerals on Wikipedia

Basic Symbols

Units (1-9)

Tens (10-90)

Hundreds (100-900)

Examples of Numbers:

Larger Numbers: