An instant New York Times Bestseller! “Unreasonably entertaining . . . reveals how geometric thinking can allow for everything from fairer American elections

In this introduction to polygons, a triangle convinces a shapeshifter to make him a quadrilateral and later a pentagon, but discovers that where angles and side

Talking math with your child is simple and even entertaining with this better approach to shapes! Written by a celebrated math educator, this innovative inquiry

The three most basic shapes -- squares, triangles and circles -- are all around us, from the natural world to the one we've engineered. Full of fascinating fact

Hunt for shapes of all kinds on this journey through a bustling city, illustrated by four-time Caldecott Honoree Bryan Collier! From shimmering skyscrapers to f