Roman Numerals Game
A free way to practice Roman numerals in both directions: choose the Roman numeral for a number, or read a Roman numeral and pick its value. The wrong answers are the mistakes people really make, like IIII for 4 or IC for 99.
Levels go from 1–20 up to years like MCMXCIV, and the converter underneath turns any number from 1 to 3,999 into Roman numerals (or back), showing how it’s built piece by piece.
How to use it in class
- Pick a direction. “123 → XII” asks for the Roman numeral; “XII → 123” asks for the number.
- Pick the numbers. 1–20 for beginners, then up to 100, up to 1,000, and years from 1000 to 3999.
- Read the breakdown. After every answer the game shows how the numeral is built, like MCMXCIV = M (1,000) + CM (900) + XC (90) + IV (4).
- Use the converter. Type any number or numeral into the converter below the game to check it or see how it’s built.
Classroom ideas
Clock faces
Look at a clock with Roman numerals and talk about why some clocks show IIII instead of IV.
Year numbers
Have students write their birth year and the current year in Roman numerals, then check with the converter.
Movie credits
Show a film’s copyright year in Roman numerals and have the class work it out.
Frequently asked questions
What are the seven Roman numerals?
I = 1, V = 5, X = 10, L = 50, C = 100, D = 500 and M = 1,000.
When do you subtract?
A smaller numeral before a larger one is subtracted, but only in six pairs: IV (4), IX (9), XL (40), XC (90), CD (400) and CM (900). That’s why 99 is XCIX, not IC.
What is the largest number in standard Roman numerals?
3,999, written MMMCMXCIX. Bigger numbers need extra symbols that aren’t part of the standard form.
Is there a zero?
No. The Romans had no numeral for zero.