Some questions to start: Can a square root be negative? Yes, there is such a thing as a negative square root. How would you deal with negative roots on the GRE? This question is actually fairly complicated, because it depends on how the GRE words the question. Let’s start with some practice problems before I […]

# Archive | Math Concepts

## Diagonals of a Polygon in GRE Geometry

Students love to skip over the basics, asking questions like: How many vertices does an octagon have? How many diagonals does an octagon have? What’s the difference between a regular octagon and, well, an octagon? And GRE geometry does delve into some complex polygon math. But before we get to that, I will begin with […]

## GRE Data Interpretation Practice Questions

Data Interpretation on the GRE Quant On test day, when you sit down to take your GRE, you will have, among other things, two Quant sections. Each Quant section will have a Data Interpretation problem set towards the end of the section. This GRE Data Interpretation set will present data, information, in some graphical form, […]

## GRE Geometry Formulas

Perhaps you recall with more than a little dread your high school geometry class: fifteen-step proofs and the law of cosines were two things you were certain you’d never see again. Well, if you are taking the GRE, you were by no means mistaken — proofs and indeed all of trig are nowhere to be […]

## GRE Math Formula eBook

Based on your suggestions, our third Magoosh GRE eBook is a compilation of must-know GRE math formulas for you to reference and memorize as you study! Though memorizing a math formula (or twelve) isn’t the only way to study for GRE Quant, knowing certain frequently-tested formulas by heart will help you improve your speed on […]

## GRE Math: What’s the Difference Between Combination and Permutation?

Do you know the difference between permutation and combination? No? You’re not alone. Combinations and permutations are the bane of many students. Yet, what I’ve noticed over the years is it’s not so much both of them that are the issue as it is which one to use for a particular problem: the combination vs […]

## How to Round to the Nearest Integer | GRE Math

What does it mean to round a number? Rounding means to make a number shorter or simpler, but keeping it as close in value as possible to the original number. Let’s take a closer look: Rounding to the nearest integer The most common type of rounding is to round to the nearest integer. The rule […]

## Magoosh Brain Twister: A Known Unknown – Explanation

Welcome back! Today, we’ll go over Tuesday’s Brain Twister problem.

## Magoosh Brain Twister: A Known Unknown

Twist your brain with this challenging GRE problem! Then, leave a comment with your work and best guess. Good luck!

## Magoosh Brain Twister: Going Through a Phrase – Explanation

Welcome back! If you haven’t had a chance to try your hand at this week’s Brain Twister, head back to the original post so you don’t accidentally see the answer here. Question A “phrase” is made up of the first seven letters of the alphabet so that each letter appears exactly once. The “phrase” […]