Roman Numerals
アラビア数字とローマ数字の変換と想起をトレーニング
About Roman Numerals
Roman Numerals is an educational trainer that helps you master conversion and recall between Arabic numbers and Roman numerals (e.g., 49 to XLIX). Each round picks its direction at random, and the value range grows as your run continues, which brings in larger symbols and the difficult subtractive pairs.
Memory & Technique Hint: To read Roman numerals quickly, anchor on key symbols: Ⅰ (1), Ⅴ (5), Ⅹ (10), Ⅼ (50), Ⅽ (100), Ⅾ (500), and Ⅿ (1000). Remember that a smaller symbol placed before a larger one means subtraction (e.g., ⅠⅤ is 4, ⅠⅩ is 9, ⅩⅬ is 40, and ⅩⅭ is 90).
Every round is generated deterministically from a seed, so the printable worksheet's answer key always matches the live game. Runs entirely in your browser and works offline as a Progressive Web App.
FAQ
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What is the general rule of Roman numerals?
Roman numerals are read left to right, adding values together. However, if a smaller numeral is placed before a larger numeral, the smaller value is subtracted from the larger one (e.g., IV = 5 - 1 = 4). -
What are the core Roman numeral symbols?
The seven core symbols are: I (1), V (5), X (10), L (50), C (100), D (500), and M (1000). -
How high do Roman numerals go in this game?
In this game, numbers scale up to 3999 (MMMCMXCIX) which is the standard ceiling for traditional Roman numerals. -
Can MemPi help me study and practice this game?
Yes! Click MemPi in the header or on the game board to summon him. He observes the board, thinks out loud, and can demonstrate moves or guide you through tricky steps.