Humans, for the most part, count in chunks of 10 — that’s the foundation of the decimal system. Despite its near-universal adoption, however, it’s a completely arbitrary numbering system that emerged ...

For centuries, the ancient Romans calculated sums with their clunky numerals: I, V, X, L, C, D, and M; or one, five, ten, 50, 100, 500, and 1,000. They knew nothing better. Then, Western Europe’s ...