A carpenter’s square (L-shaped) is probably the simplest tool to measure roof slope, which is also referred to as the roof’s “pitch”. Hold the square against the sloping roofline with the short arm ...

In "Mapmatics," a mathematician tells the stories of how math helps us track epidemics, map the seafloor, and plot a complex delivery route.

Premium cards can pay for themselves fast if you use them right. Here's when it actually makes sense to go premium.