This board shows 20 Roman numerals at the same time. You read each numeral and type the number it stands for.
Most numerals are short. About one in four comes from 1000 to 3999, and those are the ones that need care. A numeral like MCMXLIV uses the subtraction rule twice, so read it in blocks and not letter by letter.
How to play
The board shows 20 Roman numerals.
Type a number in the box at the bottom. The board accepts it as soon as it matches one of the numerals.
You can answer the numerals in any order.
The clock runs until you solve all 20, or until you give up.
Every board is new. The numerals change each time you play.
What counts in this quiz
Numbers from 2 to 3999, written in the standard form.
The seven letters are I, V, X, L, C, D and M. They stand for 1, 5, 10, 50, 100, 500 and 1000.
A smaller letter in front of a larger one means subtraction. IV is 4, IX is 9 and CM is 900.
Every answer on one board is a different number, so a typed number can only match one numeral.
What's not included — and why
The quiz never writes four of the same letter in a row. It uses IV and not IIII.
Roman numerals have no zero and no negative number, so the quiz has none either.
Numbers above 3999 need a bar over the letters to multiply them by a thousand. The quiz does not use that form.
Good to know
The Romans had no symbol for zero. Europe took the idea much later from India, through Arab mathematics.
Many clock faces print IIII instead of IV. Watchmakers keep the older form because it balances the VIII on the other side.
The year 2026 is MMXXVI. The year 1888 needs the most letters of any year in the modern era: MDCCCLXXXVIII.