As a GMAT tutor, I often hear the request for a single sheet of all of the math formulas in one place. Having this kind of tool is very helpful, in that it helps focus your efforts on applying the formulas, while also subtly helping you memorize them.
Working with the team at CC, we put together the best version of such a sheet that we have seen today and made it available to all as part of a "Practice tablet"
It is available here, for $14.99: http://www.amazon.com/gp/product/0578125862
In addition to the formula sheet, the tablet provides markers and a laminated surface to write on, just like the GMAT. We recommend doing practice questions/drills with the formula sheet open and available, so that you can easily find the formulae you need and try different approaches. As you progress in your studies you will find you need the sheet less and less as the formulae have been seared into your memory.
Feel free to take a practice test or two with the sheet available as well, but make sure most of your practice tests before the big day are done under "real" conditions... no formula sheets or notes, quiet setting, no interruptions and well rested/fed. Also, while you should hide the formula sheet, do use the laminated scratch pad and markers to simulate real test conditions, so that you are not seeing that for the first time when you take your test. It's all part of being as prepared and stress-free as possible on test day!
Hopefully, this simple tool can give you that little extra boost in your score and put you over the top! Good luck! And if you're looking for the best GMAT tutoring available anywhere, give Cambridge Coaching a call!