"Mathematics Easy reading material." . . "Hats- Children's book." . . . . . . . . . . . "Juvenile works"@en . "Juvenile works" . . "Anno's Hat Tricks" . . "Three children, Tom, Hannah, and Shadowchild, who represents the reader, are made to guess, using the concept of binary logic, the color of the hats on their heads. An introduction to logical thinking and mathematical problem-solving."@en . "Three children, Tom, Hannah, and Shadowchild, who represents the reader, are made to guess, using the concept of binary logic, the color of the hats on their heads. An introduction to logical thinking and mathematical problem-solving." . . . . . . . . . . . . . "Anno's hat tricks" . "Anno's hat tricks"@en . . . . . . . . . . "Dust jackets (Bindings)" . . . . . .