Roman Numeral Variants
Historical and decorative sources sometimes show additive spellings (IIII) or other local habits. Modern teaching and this website standardize on canonical subtractive pairs for 1–3999.
Open converter Checker Teachers
Canonical modern teaching form
Canonical forms use IV, IX, XL, XC, CD, and CM. The mistakes hub and checker explain common deviations.
Clock-face IIII
Many clock dials use IIII for 4. That is a well-known dial convention, not the modern canonical converter form IV. See clocks and IIII vs IV. Multiple historical explanations have been proposed; none should be treated as the single proven reason.
Sources & Further Reading
- Encyclopaedia Britannica — Roman numeral
- National Association of Watch & Clock Collectors — Why IIII instead of IV?