I purchased this book to use with my fourth grade daughter. Our homeschool math curriculum emphasized mental math but didn't really explain how to do it. After nine weeks, I ordered this book and it has filled the gap nicely. This book begins with the easiest strategies and builds sequentially. For each lesson, there is a page of explanation with ten practice problems followed by two sets of twenty problems each to practice the technique. There is also about a half page of instructions to the teacher for each topic to amplify what is on the student page. Some are strategies which I had figured out for myself over the years by trial and error; others are things which are less intuitive. My daughter says "This is hard," which actually means that it's making her think in a good way (makes Mom think too). She has done quite well on the exercises. I also appreciate the fact that to apply these strategies, she has to understand the way that numbers work. For example, to solve 64+77 as 64+70+7 (or as 60+70+11) requires that a student be able to break numbers apart and put them back together in a sequence which is easier to track mentally. I would recommend this book to teachers or parents wanting a systematic approach to helping students learn mental math. It's been just right for my fourth grader; it might prove more difficult for students who are still struggling to master basic math facts. If the basic facts are solid, this will help a student move to the next level.