Join Sir Cumference, Lady Di of Ameter, and their son Radius for wordplay, puns, and problem solving in this angle-packed math adventure. In the third installment of the beloved Sir Cumference series, Radius must prove himself on his quest for knighthood by rescuing a king. Sent off with the family

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

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

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

In an adventurous title that teaches math skills such as finding the area and perimeter of a rectangle and a circle, young Per must figure out how to unlock the secrets of the mysterious island of Immeter. Simultaneous.