The GMAT is known primarily as a reasoning test where rote memorization won’t necessarily help your score. Despite the lack of “recall” content within the test, there are definitely a number of mathematical expressions worth memorizing. I’m talking primarily about the fractions and percentages you’ll have to deal with on the test.
For example, you should know off the top of your head that 12.5% is equal to 1/8. Isn’t multiply by 1/8 a lot easier than multiplying by 12.5%? Knowing how to interpret the other way around, from fraction to decimal, is also helpful when you need to understand which fraction is larger. By being able to convert equal between known percentages and fractions, you’ll speed up your math calculations and save precious time during the GMAT.
Below are Tables for both Percentage to Fraction conversion and a table on Square and Cube Exponents. Memorizing these is like adding time to the test clock so I definitely recommend that you have these down pat before you walk into the test.