This year I incorporated calendar math after following The Creative Apple (http://the-creative-apple.blogspot.com). I loved the idea, but each week I would spend time trying to decide which items to put on my calendar board. I decided to create templates that I could use each week. The files are re-writeable so you can adapt the categories to fit your classroom. The template shows you each category that is included. I hope this will save you time as it has me.