books.google.com - This valuable guide includes: Comprehensive coverage of the arithmetic, algebra, and geometry concepts tested by the GMATAn intensive, back-to-basics, tutor-led approach to math reviewHundreds of practice exercises to increase speed and accuracy...http://books.google.com/books/about/Kaplan_GMAT_Math_Foundations.html?id=szGYWUUWCOwC&q=perfect+square&utm_source=gb-gplus-shareKaplan GMAT Math Foundations