For the most part the book is well though out and the material presented clearly. I don't understand why some calculations round the result up or down. It doesn't seem to follow the rules of 50 cents above is rounded up and 49 cents and below gets rounded down. Page 172 is one example. It calculates to $81,667.35, but the answer is rounded it up.to $81,668. I'm concerned the tests do this very thing. Another thing I would change is to add explanations to all the answers. Even the true true and false answers. Give a page number where the information can be found. Since the test for this topic for the certification requires a testing center, the answers for the test would be helpful.