I am begging you not to buy this book, I am a highschool junior trying to prepare for The ACT's so I was taking the Diagnostic Test at the begining of the book and in checking my answers I realized that I had WAY too many wrong answers, so i checked the Answer Explanations for one of the questions I got wrong, the question was and I quote "The original price of a computer was $1200. What was the price of the computer after two 10% mark downs?" F. $960 G. $972 H. $980 J. $1,000 K. $1,072 The correct answer would be of course G. $972. So I went to check my answers in the back of the book and it tells me the correct answer is F $960. I dont understand how this is possibly true so I go to the Explanations where it says (and again I quote): "Marking down $1,200 by 10% reduces the price by 10% of 1,200=120. The new price is 1200-120=1080. Marking that down 10% reduces the price by 10% of 1080=108, so the final price is 1080-108=972" This is answer G not F!!