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

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,

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 g

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

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 gu