Gr 4–6—This creative team introduces the components of algebra and geometry as cartoon-style characters. The book begins with a brief introduction to the subject of mathematics and Pythagoras. Then, the concepts are grouped together in eight chapters, including "Counting Crew" (Roman numerals, base 10, etc.), "Graph Gang" (vector, line, etc.), "Shape Sisters" (perimeter, area, etc.), "Trig-Athletes" (sine, cosine, etc.), and "In the Round" (circle, pi, etc.). Each chapter begins with an introduction and then the concepts are presented on a spread. One page features a drawing of the concept's character, while the opposing page provides a brief introduction to its characteristics and personality. The author describes a Mobius strip in detail, but never calls it by name. There is some crossover between this title and Green's Math: A Book You Can Count On (Kingfisher, 2010). The information is presented in a chatty tone. For example, Negative Number is introduced as living in, "…chilly, subzero zone. It's brrr, no doubt!" and is portrayed as an ice cube holding a thermometer. Along with the narrative, which is written in the first person from the concept's point of view, basic information and key facts are provided in bullet points. This book is certain to appeal to number lovers and would be an effective supplement to a mathematics curriculum.—Maren Ostergard, King County Library System, Issaquah, WA