With computers and calculators all around us, we tend not to do very much math once weve completed our college quantitative requirements, but the GMAT will require you to be able to do math without a calculator so you will need to retrain your mind. Fortunately, day to day life provides countless opportunities to perform simple math by hand or in your head, and the more you can do so the easier a time youll have when you do sit down to do GMAT math. Practice calculating tips when you eat out; estimate how long it will take you to reach your driving destination at two different average speeds; notice prime numbers and multiples of 3 when youre writing down phone numbers; do quick calculations on paper before you plug the numbers into Microsoft Excel. Simply thinking mathematically can help you to retrain those atrophied portions of your brain, and that will allow you to eventually focus more of your study time and energy on GMAT specific question types and strategies.