Consider this about number units: English separates large numbers with commas, advancing in thousands—million, billion, trillion. There’s no single word for “ten thousand.” Chinese, however, uses units of ten thousand (万, 亿, 兆…). We use “million” (百万) more now, but that’s recent, due to handling larger figures. “Million” is a combination, not a base unit like “ten thousand.”

It’s curious. We have distinct words for smaller place values: ones, tens, hundreds, thousands, ten thousands. Why not for larger numbers? We simply didn’t need them! Daily life, particularly anciently, rarely required such large numbers.

Rulers, however, dealt with massive figures. Inventing a word for every place value would be impractical. The solution? Use the largest common unit as a base. This avoids new concepts and simplifies comparisons. Within the same order of magnitude, the specific unit is less important. Large differences are clear from the unit, and smaller ones remain manageable.

This hints at a difference in scale between the ancient Chinese and English-speaking worlds, reflected in geography, population, and agriculture. It’s well-known, but it might be the core reason for the East-West difference in number units today.