Roman Numerals 1 to 20

Roman numerals 1 through 20. Rome's number system uses letter combinations — still seen on clock faces, book chapters, and movie dates.

20 is a landmark letter: a single symbol, XX, carries the whole value, and the landmarks step by alternating factors — five, then two (I, V, X, L, C, D, M for 1, 5, 10, 50, 100, 500, 1000). Only three places allow subtraction — I before V or X, X before L or C, C before D or M — and one less than a landmark forces the trick: 20 − 1 = 19 = XIX. The current year reads the same from the top down: 2026 = MMXXVI — MM for the thousands, XX for the tens, VI for the units. Clock faces often print IIII for four rather than IV — a design tradition, not arithmetic. Numbers add when each symbol is smaller than the one after; when a smaller letter stands before a larger, its value is taken away.