Unlike cheaper calendars that i had to paperclip the pages together to keep from flopping over, these pages are sturdier and don't cause an issue. The calendar shows important dates and also the moon's fazes.
This is a beautiful book with colorful diagrams that help visualize geometric shapes and their elements. I personally feel that the hardback book is the best format for digging into this text. Absolutely great, particularly for the vudual learner.
It's worthless for kindle because the book uses colors to teach. It's wrong to even offer this for the kindle.