I have long been a fan of the poems for two voices books by Paul Fleischman. This book puts a twist on the idea by covering math topics in poems. It's a really unique and engaging way to memorize a math concept, reciting it as a poem. A poem for two voices is a poem recited by two people where sometimes the same words are said in tandem, sometimes alternately, and sometimes, the speakers speak at the same time saying different things.
Here is a sample of part of a poem from the book: (The first column is the first speaker and the second column, the second - shown smaller than actual size) 
Some of the math concepts in the poems are fairly simple ideas that would pertain to a grammar school student, however most of the ideas are for middle schoolers or high schoolers. There were a few math concepts I had never heard of, such as fractals, (the geometry of nature), Fibonacci numbers (adding the last two numbers in a series to give the next number), and Mobius strips (circular strip with a twist in it).
While you don't learn everything you need to know about the math concepts in the poems, you get an introduction to the idea and the basic or interesting facts. For tessellations, the reader learns that not all figures tessellate; for triangles, the reader learns that the angles in the figure must equal 180 degrees. Some of the accompanying illustrations are also instructive. I could not have visualized the Mobius strip without the drawing of it.
This is a fun way to talk about these concepts. Trying to say the poems as a team takes a lot of concentration and brings a lot of laughs along the way. The book would make a great addition to a living math program or be a nice break from a formal textbook program.
Recommended for grades 4-12
