Instruct: Classify a given Amazon review into positive or negative sentiment.
Query: Needs improvement!

The explanations in this book could be more concise for students who have other assignments to study and fulfill. Throughout all my years in reading mathematical textbooks, this one does not head straight-to-the-point. The author spends more time introducing the subject than explaining how one step is derived from another in the examples, which leaves the student to spend time figuring how one concept abruptly transitions into the next. Aside from that, the exercise questions sometimes do not relate to the examples given in the book.