Radius, the son of Sir Cumference and Lady Di of Ameter, sets off on his first quest with the family medallion (a protractor) in hand. The geometry wordplay is more engaging than the overlong story itself, and although the illustrations convey the medieval setting, they don't clearly depict how to use a protractor to measure angles.

Gr 1-4-Radius, the son of Sir Cumference and Lady Di of Ameter, ventures on a heroic quest to earn his knighthood. He first proves his ability to make a "knightly right angle," as Sir D'Grees has trained him, and then doubles the right angle to make a straight angle. So he is sent off with the family medallion, in the shape of a circle (cardboard medallion included), to rescue the missing King Lell. Falling bridges, a cryptic riddle, a crocodile-infested moat, and a winding labyrinth all must be mastered before finding the king and his twin dragons, known as "Pair of Lells." Sir Cumference has something to offer a wide range of readers. Some will be too young to understand the math and the word puns but will enjoy the story of a knight rescuing a king. Others will puzzle over the math and how to use the protractor (medallion) to solve the riddle. This group will be helped by the somewhat primitively painted pictures, which give clues to these angled decisions and enhance the story of a brave knight on his quest. Still other children will note the story, groan at the puns, and wish for more sophisticated illustrations. This book has a stronger story line than that found in most math books. It should be useful to creative teachers and fun for the right child.-Nancy A. Gifford, Schenectady County Public Library, NY Copyright 2001 Cahners Business Information.