It is a great book for introducing polygons, especially when paired with manipulatives. I pass out a bag of craft sticks, usually 10, to my students. As we read the book, we use the sticks to form each polygon. The book starts with a triangle that is not "satisfied" with its three sides, and wants more, hence the name The Greedy Triangle. It goes all the way to an octagon if I'm not mistaken. Students can see how adding the extra sides makes extra vertices, and the polygon grows larger. It is also an A.R. or Accelerated Reader book, so students can test and earn points. (If you are self-contained or if your ELAR teachers accept A.R.) Afterwards, you can journal, and pay special attention to all the four sided polygons that are possible. I like the way it shows so many real world applications of each shape in such a clever, read aloud format. Marilyn Burns also has a great website with lots of great ideas. It is

www.mathsolutions.com.

Good luck to you.