As pennies begin to disappear, states are grappling with a "rounding" problem for cash purchases that would have included them in the past.

States are setting new rules for cash purchases after the U.S. Mint stopped making pennies and the 1-cent coins get scarcer.

He lit up the 1970s with a string of hits, before falling out of the public eye. But was any man ever more connected? He discusses extraordinary encounters with Muhammad Ali and Keith Moon – and why ...

Celebrate Pi Day and read all about how this number pops up across math and science on our special Pi Day page. Grab something circular, like a cup, measure the distance around the circle, and divide ...