Who doesn’t love a good math holiday? Most people know about Pi Day (3/14), but there are even rarer days on the calendar ...

The Riemann Hypothesis is one of the most famous problems in that set. It’s about prime numbers. That’s any whole number that can only be divided by 1 and itself – like 2, 3, 5, 7 and 11.

Even if you’re a Strava refuser or a smartwatch shunner, the purest of purist runners invariably have an ideal finish time in their heads when they arrive at a start line. If you’re going to hit or go ...