King Arthur has issued a challenge. The first knight to find the sword Edgecalibur will be the next king. Join Sir Cumference, Lady Di of Ameter, and their son, Radius, as they race to help their friend, Vertex, find the sword and discover the secrets of cubes, pyramids, cylinders, and cones.

A funny and pun-filled retelling of “The Sword and Stone” that introduces readers to mathematical angles. King Arthur has hidden his sword, Edgecalibur and issued a challenge to the knights. The first knight to find the sword will be the next king. Can Sir Cumference and Lady Di point Radius's best friend, Vertex in the right direction? Will Vertex's sharp thinking give him the edge? Join Sir Cumference, Lady Di of Ameter, and their son, Radius, in this new adventure where they race to help Vertex find the sword and discover the secrets of cubes, pyramids, cylinders, and cones.

A funny and pun-filled retelling of “The Sword and Stone” that introduces readers to mathematical angles. King Arthur has hidden his sword, Edgecalibur and issued a challenge to the knights. The first knight to find the sword will be the next king. Can Sir Cumference and Lady Di point Radius's best friend, Vertex in the right direction? Will Vertex's sharp thinking give him the edge? Join Sir Cumference, Lady Di of Ameter, and their son, Radius, in this new adventure where they race to help Vertex find the sword and discover the secrets of cubes, pyramids, cylinders, and cones.

When Sir Cumference and his wife, Lady Di of Ameter, host a massive surprise birthday party for the king, they must figure out a way to quickly count all the guests who are in attendance.

For fans of the Sir Cumference series with Pi on their mind, here is the second installment in this fun look at math and language. This time the math adventure is centered around a potion that changes Sir Cumference into a fire-breathing dragon. Can Radius change him back? Join Radius on his quest through the castle to solve a riddle that will reveal the cure. It lies in discovering the magic number that is the same for all circles. Perfect for parent and teachers who are looking to make math fun and accessible for everyone.

Join Sir Cumference, Lady Di of Ameter, and their son Radius for wordplay, puns, and problem solving in this geometry-packed math adventure. King Arthur was a good ruler, but now he needs a good ruler. What would you do if the neighboring kingdom were threatening war? Naturally, you'd call your strongest and bravest knights together to come up with a solution. But when your conference table causes more problems than the threat of your enemy, you need expert help. Enter Sir Cumference, his wife Lady Di of Ameter, and their son Radius. With the help of the carpenter, Geo of Metry, this sharp-minded team designs the perfect table conducive to discussing the perfect plan for peace. The first in Sir Cumference series, Sir Cumference and the First Round Table makes math fun and accessible for everyone.

To earn his knighthood, Radius uses a circular medallion to find and rescue a missing king.