While I appreciate this book, I am a little irked at the quality of the editing. I have already found at least three mistakes. Where there should have been a -8, there was a -7, for example in a couple of the answers in the appendix. I would love to know that there is a revamped version somewhere with the correct answers inside so that newbies to pre-algebra, don't think they are going bonkers because their answers are not turning out the way they should be turning out as per the appendix.
I also yearn for some deeper explanations on some of the points. The book at times is not thorough enough. I prefer the Demystified series for math.