If you love number-based puzzles, this book will challenge you and provide hours of entertainment.Number fill-ins are solved through logic and process of elimination (no math involved), and are great for improving your powers of concentration. Includes over 80 puzzles. Puzzle grid on left page and number list on right, for plenty of room to work the puzzles. Includes answer key in the back of the book. Spiral-bound, 192 pages.