Bake Infinite Pie with X + Y. ­

K-Gr 3–Cheng uses the act of pie baking to demonstrate mathematical concepts, specifically the idea that shaping and reshaping dough and fillings can produce an infinite number of results. Two children named X and Y join brainy Aunt Z in the kitchen, where they learn that combining butter, flour, and water is not only useful for making pastry, but also for observing a never-ending array of geometric forms, an expanding number of points and exponential layers. Cheery, playful illustrations and a tale based on yummy desserts will have some appeal to young readers, though the continual cutting of shapes gets repetitive. The story itself is rather bland. In addition, there’s a disconnect between the main text, which is geared toward a young audience, and the substantial back matter, which includes an impressive introduction to sophisticated concepts such as Zeno’s paradox, fractals, and convergent sequences.