Ok, my biggest problem on the GMAT is time. As I have an ADHD (and the GMAC denied my extra time request, because apparently, you can still have an ADHD, but if it isn't severe enough to impact your every day life, you don't fall under the ADA guidelines and therefore do not need extra time... i.e. i hate the gmac), I end up getting killed on the math section. I have been looking for ways to do calculations much quicker than what I am used to, and came across some books on amazon that teach "speed math." One book in particular, The Trachtenberg Speed System of Basic Mathematics," seems to teach a mucher "faster" math method.
Can anyone recommend a good book, or does anyone have any notes that teaches this speed math? They give some examples and the concepts/tricks seem AMAZING.