CDXV

CDXV is the Roman numeral for the number 415. It is formed by combining the subtractive pair CD, which denotes 400, with XV, which denotes 15, resulting in 400 + 15 = 415. In the modern convention of Roman numerals, CDXV is a standard way to write four hundred fifteen without using an additive sequence like CCCCXV.

Uses and context: CDXV appears in contexts where Roman numerals are used to denote years, chapters, volumes, or item numbers. For example, it may be seen in inscriptions, historical documents, or lists that employ Roman numeral dating or labeling. Because Roman numerals do not rely on place-value notation, CDXV encodes the value without requiring separators.

Variants and notes: An alternative, though archaic, way to express 415 is CCCCXV, which uses additive notation rather than the subtractive CD form. In most contemporary usage, subtractive notation (CDXV) is preferred for clarity and brevity. The sequence fits within the broader system where smaller values placed before larger values indicate subtraction, while repeated larger values beneath a threshold are added.

Related topics: Roman numerals, CD (400), XV (15), Roman numeral subtractive notation, year notation in ancient and medieval contexts.