This picture book is about how two young children, X and Y, work with their Aunt Z to bake infinite pie.
Aunt Z helps them discover how to use “flour, butter, and water” to make pastry in an infinite number of ways to create pies. X makes dough into circles while Y makes the dough into a triangle. They fill their pies with strawberries, chocolate, and banana. Some of the pies have four sides, while others have eight.
The book is best for fourth grade and up. The concepts like infinity are more advanced and it is difficult for young students to understand. For example, X says, “My round pie has infinite corners!” This is a complex and abstract idea for younger learners to visualize. And like Y says, “But…it doesn’t seem like it has any corners.” Most students will need a teacher or parent to explain how a circle can be comprised of infinite corners.
A teacher could use this text as an opportunity for older students to identify mathematical concepts like fractals and exponentials. The author uses triangles to create a Koch snowflake out of pastry. She also shows exponentials by having the bakers fold puff pastry repeatedly.
This is a fun book and the bold colors and pictures that illustrator Ren drew of Aunt Z, X, and Y are enjoyable. The Asians in the book look like people we might know. They are not stereotypical. Use this book to introduce readers to complex ideas like infinite corners, X and Y axes, different geometric shapes, and infinity.
A short Interview with author and mathematician of the book, Eugenia Cheng
IE: What grades is the book Bake Infinite Pie with X+Y geared toward?
Eugenia Cheng: Bake Infinite Pie with X+Y is listed for ages 4 to 8, but I can understand why it might seem surprising. The mathematical concepts might seem quite advanced, but the ideas are things that can spark the curiosity and imagination of small children of all ages.
It would take some advanced math to make those ideas precise and fully explain the math of them, but I love talking about the ideas with children without having to go into the full math explanations. I think too often we think we’re supposed to understand all the math we see, but actually nobody really understands these things. I think it’s more important to think about them and let children’s minds boggle and wonder, rather than trying to get them to understand everything.
Imagine if it were a book about the weather. It might introduce children to rain, snow, thunder, lightning, hurricanes and tornadoes, but we wouldn’t expect them to understand all the meteorology that causes those phenomena.
IE: How can teachers explain the complex concepts like infinity?
EC: For children of this age, I don’t think the concepts need to be explained, rather explored. We can set small children off thinking about the ideas, and then exploring them, just like we explore music and art rather than explaining them. We can set them off thinking about infinity as something so big it goes on forever.
IE: How can parents teach the concepts of infinity, fractals, and exponentials to their young children?
EC: I have talked to many parents who are afraid to talk about math with their children because they don’t feel they understand it themselves. I would just urge them to talk about it anyway! Parents can explore the ideas with their children and if the children ask them questions they don’t know how to answer that’s great, and they could talk about how to go about investigating it together. The internet has a lot of helpful explanations of math concepts, and I believe in celebrating children when they ask a math question an adult doesn’t know how to answer.