This book has some good information, but it's obvious that they skipped all the steps needed to locate the errors. It's supposed to have the correct answers for test questions. However, multiple times up to chapter 7, I'm finding that the answer key is off, obviously off by getting the numbers mixed up and so on. This book can still be helpful, but it's very disappointing to find this many errors after paying good money for the book. I'd consider going to other publishers before buying again from these people.