Roman numeral letters
- I = 1, V = 5, X = 10, L = 50, C = 100, D = 500, M = 1000
- Subtractive pairs: IV = 4, IX = 9, XL = 40, XC = 90, CD = 400, CM = 900
Examples
- 1 = I, 4 = IV, 9 = IX, 14 = XIV, 40 = XL, 90 = XC, 400 = CD
- 1492 = MCDXCII, 1999 = MCMXCIX, 2026 = MMXXVI
- 3999 = MMMCMXCIX (the standard maximum)
FAQ
Why no zero?
The Roman numeral system was developed before the concept of zero entered Western mathematics. There's no Roman symbol for zero — for "nothing" they wrote "nulla".
Why is 4 written IV, not IIII?
The subtractive form (IV = "one before five") became the standard rule in late antiquity and is universal today. IIII still appears on some clock faces for symmetry, but mathematically IV is correct.