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Frequently Asked Questions
What are Roman numerals?
Roman numerals use letters to represent numbers: I=1, V=5, X=10, L=50, C=100, D=500, M=1000. They originated in ancient Rome and are still used today for clock faces, book chapters, movie sequels, and year numbering in formal contexts.
What is the subtractive rule?
When a smaller value appears before a larger one, it is subtracted. IV = 4 (5−1), IX = 9 (10−1), XL = 40 (50−10), XC = 90 (100−10), CD = 400 (500−100), CM = 900 (1000−100). This avoids repeating more than three identical symbols.
What is the largest Roman numeral?
Standard Roman numerals go up to 3,999 (MMMCMXCIX). The number 4,000 would require MMMM which violates the rule of no more than three consecutive identical symbols. Some systems use a bar over a letter to mean ×1000 (V̄ = 5,000).
Are Roman numerals still used today?
Yes. Common uses: copyright years in movies and TV (© MMXXIV), Super Bowl numbering (Super Bowl LVIII), clock faces, book front matter (page numbering), outlines, monarchs and popes (King Charles III, Pope John Paul II), and formal event names.