Charlie Piechart and the Case of the Missing HatBook - 2016
This math mystery takes place at schoolwhen a purple, sparkly cone-shaped princess hat goes missing! Margot needs her hat in time for the school play (today!), so Charlie and his dog companion, Watson, are on the casefinding evidence of sparkles and purple paint and keeping on the lookout for geometric clues that might lead to the missing hat.
Publisher: New York, NY :, Katherine Tegen Books, an imprint of HarperCollins Publishers,, 
Edition: First edition
Characteristics: 1 volume (unpaged) : color illustrations ; 27 cm