numeral

So he defined a Type I civilization… that’s a Roman numeral one… as using close to what humanity was using at the time: around 40 quintillion ergs per second.

Way back in 1202, Leonardo of Pisa, also known as Fibonacci, wrote a book in which he introduced Europe to the Arabic numerals we use today.

Way back in 1202, Leonardo of Pisa, also known as Fibonacci, wrote a book in which he introduced Europe to the Arabic numerals we use today.