数字とローマ数字を相互変換
Numbers above 3,999 use vinculum notation: a line above a numeral multiplies its value by 1,000.
So XCIXDCLXXV = 99,675.
Did you know?
Can People Actually Read Them?
Ask the average person what number Super Bowl LVIII is, and you'll get a lot of confident wrong answers. But it doesn't matter. The Roman numerals aren't there to communicate a number efficiently. They're there to communicate importance. When you see LVIII, you don't need to know it's 58. You need to feel that this is an event with history and weight.
Read more →Fibonacci's Sales Pitch
Fibonacci didn't invent Hindu-Arabic numerals — they originated in India around 500 AD. But his 1202 book Liber Abaci was essentially a 600-page argument that these new numbers were better for business. He showed European merchants how place value and zero could transform trade and banking. He was right. By 1500, the debate was over.
Read more →ローマ数字はどこから来たのか？
ローマ数字は手の合図や数え棒に由来すると考えられています。線のIは指1本を、Vは5を表す親指と指の間の隙間を、Xは10を表す交差した両手を表しています。L、C、D、Mはギリシャ文字のカイ、シータ、ファイを変形させたもので、それぞれ50、100、500、1,000を表します。時が経つにつれ、これらの記号は今日知られているラテン文字へと変化しました。ローマのアルファベットには0がありません。0の概念は、インドが紀元600年頃 / 10600 HEに発明するまで完全には発達しなかったためです。