In the second book of the series, a potion has changed Sir Cumference into a fire-breathing dragon! It's up to his son, Radius, to discover the magic number that will turn his father back. Will he make it on his quest through the castle in time?
In this wonderfully illustrated series, go on math adventures with Sir Cumference, Lady Di of Ameter, and their son Radius. Each book presents a mathematical concept in such a way that it allows students to fully comprehend "how" and "why" the characters solve their unique problems.