The bat-and-ball problem is a famous math puzzle that more than half of people—even Harvard graduates—get wrong. It's ...

Every few months, the Internet eats itself over some kind of viral riddle or illusion, each more infuriating than the last. And so, like clockwork, this maddening math problem has gone viral, ...

The question goes: "A bat and a ball cost $1.10 in total. The bat costs $1.00 more than the ball. How much does the ball cost?" Is your knee-jerk response that the ball costs ten cents? That is a ...

Get out your timer and number two pencil to see if your arithmetic skills are still sharp.