Discrete Math Workbook: Interactive Exercises

I was looking for a book to review discrete mathematics that I had taken 8 years ago using the obtuse Rosen book (Discrete Mathematics and Its Applications). I ordered another book on discrete math and the bookstore sent me both my ordered book and this workbook (I guess to get rid of it). Wow. This book offers a fantastic summary of discrete math, has good sample problems, and has tons of problems for the student to work out (along with answers to all the problems at the end of the workbook). The actual book I ordered is ok. This one, however, is definitely a hidden gem.