If you need to know it, it's in this book! Cracking the GMAT, 2012 Edition includes everything you need to know to master the Math, Verbal, and Analytical Writing Assessment sections of exam. With all questions & answer/explanations linked together for easy on-device viewing, it includes:
2 full-length practice exams with answers and scoring
A thorough review of all GMAT topics, including data sufficiency, arithmetic, algebra, geometry, sentence correction, reading comprehension, critical reasoning, and more
Tons of sample problems with detailed answer explanations to show you exactly what to expect on the GMAT
Key GMAT strategies and principles for making the most of your test prep and maximizing your score
Expert tips, hints, and advice