Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Great math problems, questionable explanations

This math book is a great problem book but seems to lack in some explanations of the concepts. Also, the book contains some extranneous concepts and formulas and does not necessarily present the material in a friendly manner. The book is very straightforward--something which I find to be important in a mathematics book. The problems are interesting and challenging, but the book should provide solutions to all of them, not just some.