Commercial rounding in Python
As it turns out, Python does not do commercial rounding. What is commercial rounding? For most digits, the direction of rounding is clear. There are some special cases though: Do I round $0.5$ to $0$ or to $1$? In commercial rounding, this “$0.5$” problem is solved by “rounding away from zero”, meaning: For positive numbers, round up; for negative numbers, round down. This makes perfect sense for a mathematician, but others might need examples, so here are some1: ...