In the third century BCE, Apollonius of Perga asked how many circles one could draw that would touch three given circles at exactly one point each. It would take 1,800 years to prove the answer: eight ...

Compare four sets of pattern blocks. Use pattern blocks to make different shapes. Warm up with a Mystery Math Mistake to tell whether Dotson's 10-frames represent a number less than his focus number.

Symplectic geometry is a relatively new field with implications for much of modern mathematics. Here’s what it’s all about. In the early 1800s, William Rowan Hamilton discovered a new kind of ...