GRE & GMAT: Math Topics to Refresh

Many students applying to graduate school will scarcely have taken a college course in math. In large part, that is a very small impediment to success on the GRE or GMAT. The math covered in many common undergrad surveys – calculus-based economics, accounting, physics, for example – are not covered at all on the test. The GRE and GMAT primarily tests reasoning skills that draw superficially on substantive math knowledge: they are less interested in what you know than in how you apply basic knowledge to novel problems. What’s more, the test now features an on-screen calculator, obviating the need to rehearse arithmetic tricks.

Most signs point to repeated practice, prioritizing questions, and learning some basic strategies as sufficient for success on the quantitative sections of the test. In reviewing missed questions, all those rules from high school will come back, more intuitive and clear than they ever were back then.

This is mostly right. Mostly. There are a few math topics that arise consistently and trouble students aiming for competitive scores, though, and require a bit more persistence. Memorizing math facts is a drag, much like studying vocabulary. Like vocabulary work, though, it is often necessary to get those stubborn final questions testers need to reach their goal.

In addition to limbering up those rusty algebra and geometry skills, the following topics commonly require a bit more work and memorization:

• Percent Change: make sure that you are being sensitive to the base that you are taking the percentage of. Research an approach, using ratios or straight algebra, that will always work and makes sense to you.
• Special triangles: these come up, often in veiled form, on every test. If you often confuse them or have never learned them, make flashcards for 30-60-90 and 45-45-90 triangles. Then do enough practice questions that they dance before your closed eyes as you drift to sleep.
• Exponents: very few of us use exponents in the ordinary course of our lives, and the rules are fairly subtle.
• Permutations and Combinations: know these formulas, and be able to easily distinguish which to use in a given context. These are often not needed to get a competent score, but beware that they are fair game and some of the hardest questions the GRE has to offer.