"Charlie! Help!" Charlie's friend Margot is missing her hat. "It's a princess hat-purple and cone shaped. I need it for tonight's play!" With Watson along, Charlie searches for clues all over school. They find a cylinder-shaped hat and a half-sphere hat and lots of purple sparkles, but it's shaping up to be a tough case. Will Charlie and Watson find Margot's hat before the play begins Three Cheers for Charlie Piechart and the Case of the Missing Pizza Slice "A lighthearted tone and newcomer Comstock's playful graphics, which have a weathered, retro quality, make the lesson go down as easy as pie."-Publishers Weekly "Kids will have fun following Charlie as he solves the mystery and reinforce their fraction skills along the way."-Kirkus Reviews "Charlie! Help!" Charlie's friend Margot is missing her hat. "It's a princess hat-purple and cone shaped.

I need it for tonight's play!" With Watson along, Charlie searches for clues all over school. They find a cylinder-shaped hat and a half-sphere hat and lots of purple sparkles, but it's shaping up to be a tough case. Will Charlie and Watson find Margot's hat before the play begins Three Cheers for Charlie Piechart and the Case of the Missing Pizza Slice "A lighthearted tone and newcomer Comstock's playful graphics, which have a weathered, retro quality, make the lesson go down as easy as pie."-Publishers Weekly "Kids will have fun following Charlie as he solves the mystery and reinforce their fraction skills along the way."-Kirkus Reviews.