I just have the OG11
and the maths explanations are decent but sometime I'm stuck on simple problems just because I don't know the theory - like what happens to a power when you square it or divide, etc
Which is the best book for this kind of stuff? I'm not really interested in good practice questions - focus should be the theory behind the question
I was thinking of MGMAT but there are 3 or 4 separate book afaik
You are absolutely on the right track - get a book that covers math concepts, not tricks or strategies for test taking. Many confuse the two and you can't get into the strategy without having a good understanding of fundamentals.
I have used Kaplan Math Workbook
and it was very useful and not too into the weeds. The ony disadvantages were lack of probability or combinations problems.
Also, the book by Cliff's is recommended by a few people - it has solid 41 reviews and 5 stars on Amazon: http://www.amazon.com/gp/product/082202 ... 0822020335
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