This holiday-themed brainteaser looks simple, but it's quietly tripping up adults everywhere. A math teacher walks us through ...

Katie has a PhD in maths, specializing in the intersection of dynamical systems and number theory. She reports on topics from maths and history to society and animals. Katie has a PhD in maths, ...

We like to think that we're pretty good at math, especially after years of schooling. But every once in a while, a simple third-grade math problem manages to trip us up and make us question our ...