The End of Error

2 Building up to the unum format

Positional notation and the concept of zero are at least as ancient as the abacus. The oldest known forms of the abacus were round stones in troughs, not beads on rods. The Latin word for stone is “calculus,” which makes it clear where the word “calculate” comes from. Europeans learned enough about the positional system from Arab traders that by 1202, Fibonacci published a description of it in Liber Abaci. The woodcut above is from Margarita Philosophica by Gregor Reisch (1503), and depicts a competition between an “algorist” using Arabic numerals and an “abacist” using a four-decimal abacus. Apparently this ...