Pi, a mathematical constant denoted by the Greek letter π, is the ratio of a circle's circumference C to its diameter d: π = C/d. The circumference of a circle is, in turn, equal to 2πr, where r is ...

What is the most important number in the entirety of mathematics? Ok, that’s a pretty silly question – out of infinite possibilities, how could you possibly choose? I suppose a big hitter like 2 or 10 ...