Articles published in Math Basics

GRE Math for People Who Hate Math: A Gentle Introduction to GRE Divisibility Problems

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GRE Math for People Who Hate Math: A Gentle Introduction to GRE Divisibility Problems by Chelsey CooleyDid you know that you can attend the first session of any of our online or in-person GRE courses absolutely free? We’re not kidding! Check out our upcoming courses here.


12 is divisible by 3. 24,700 is a multiple of 100. x/15 is an integer. 6 is a factor of 17k. All of this language — divisible, multiple, integer, factor — signals that you’re about to begin a divisibility problem. Do you find these problems intimidating? Do you sometimes have no idea where to start? If so, this article offers a simple, painless way of thinking about divisibility that you can use on a wide range of GRE problems. Read more

Let’s Have Fun with GRE Exponents

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blog-exponentsYou may already know the basic rules of exponents for the GRE. These rules tell you what to do if you want to multiply or divide two exponential numbers, or raise an exponent to another power. Once you’ve memorized them, exponent problems become exponentially easier (I’m so sorry). But there are two types of exponent problems that many students find intimidating, because the basic rules just don’t seem useful. In this article, we’ll go over those two problem types, how to recognize them, and what to do if you see one. Read more

Here’s How to Create Your Own GRE Quant Cheat Sheet

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You can attend the first session of any of our online or in-person GRE courses absolutely free. Crazy, right? Check out our upcoming courses here.


Do you remember, when you took exams in high school or college, being allowed to bring a one-page ‘cheat sheet’? I always spent days putting those cheat sheets together in my tiniest handwriting, summarizing an entire semester’s notes on a single page. The funny thing is, by the time I took the exam, I almost never needed to look at the cheat sheet I’d created. After spending all of that time creating it, I had practically memorized my notes. So, even if you can’t bring a GRE Quant Cheat Sheet to the test, you can still benefit from creating one. Synthesizing your notes and thoughts on a single page will give you the ‘big picture’ view of a topic—and will teach you what you do and don’t know. Read more

Here’s How to Always Know What to Do on Any GRE Problem

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You can attend the first session of any of our online or in-person GRE courses absolutely free. Crazy, right? Check out our upcoming courses here.


“When I See This, I Will Do This”: A GRE Study Tool

“I know all of the rules, but I’m nowhere close to my goal score.”

“When I study, I understand everything right away. But when I took the actual GRE, I couldn’t make it happen.”

“I never know what to do when I see a Quant problem for the first time. If somebody tells me how to set the problem up, I can do it perfectly, but I can’t get started on my own.”

“I get overwhelmed by Verbal questions. I’ll think that my answer makes sense, but then I’ll review the problem and realize that there were a dozen different things I didn’t notice.” Read more

Here’s the Safest Way to Handle GRE Percentage Problems

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You can attend the first session of any of our online or in-person GRE courses absolutely free. Crazy, right? Check out our upcoming courses here.


When you take the test, you need a strategy for GRE percentage problems that works every time. Here’s that strategy, in four easy steps.
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This simple approach will help you avoid mistakes on GRE algebra

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Blog-SimpleApproachGRE high-scorers might not be smarter than everyone else, but they do think about the test differently. One key difference is in how high-scorers do algebra. They make far fewer algebraic mistakes, because, either consciously or subconsciously, they use mathematical rules to check their work as they simplify. Here’s how to develop that habit yourself. Read more

The GRE’s not a math test – it’s a foreign language test!

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Blog-GRE-LanguageImagine that you asked a friend of yours what she got on the Quant section of the GRE. Instead of answering you directly, she said “let’s just say that 4 times my score is a multiple of 44, and 3 times my score is a multiple of 45.”

Could you tell what score she got? If not… you may need to work on your GRE translation skills!  Read more

Manipulating Inequalities and Absolute Value on the GRE

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Did you know that you can attend the first session of any of our online or in-person GMAT courses absolutely free? We’re not kidding! Check out our upcoming courses here.


Most people dislike absolute value, and inequalities can tie us up into knots. Put them together, and we can have some major headaches! Let’s test one out.

Set your timer for 1 minute and 15 seconds for this Quantitative Comparison problem and GO! Read more

Using Smart Numbers to Avoid Algebra on the GRE

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Many word problems seem to require us to write formulas in order to solve. Certain problems, though, qualify for a neat technique: Smart Numbers. We can actually pick our own real numbers and use them to solve!

Set your timer for 2 minutes for this Fill-In problem and GO! (© ManhattanPrep)

* Lisa spends 3/8 of her monthly paycheck on rent and 5/12 on food. Her roommate, Carrie, who earns twice as much as Lisa, spends ¼ of her monthly paycheck on rent and ½ on food. If the two women decide to donate the remainder of their money to charity each month, what fraction of their combined monthly income will they donate? (Assume all income in question is after taxes.)

 

(No answer choices given; this is a fill-in-the-blank)

 

GRE algebraWe’ve got two women, Lisa and Carrie, and they each spend a certain proportion of income on rent and on food. Annoyingly, the fractions don’t have the same denominators; even more annoyingly, the two women don’t make the same amount of money. All of that will make an algebraic solution challenging.

Here’s what an algebraic solution would look like. Let’s call Lisa’s income x. She spends (3/8)x on rent and (5/12)x on food. Add these together:

(3x/8) + (5x/12) = (9x/24) + (10x/24) = 19x/24

Subtract from 100%, or x:

24x/24 “ 19x/24 = 5x/24

Lisa donates 5/24 of x, her income, to charity. What about Carrie?

Carrie’s income is equal to 2x (because she makes twice as much as Lisa). How much does she spend on rent and food?
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Translating Words into Math: Part 2

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translateThis is the second part of a two-part article on the topic of translating wordy quant problems into the actual math necessary to set up and solve the problem. Click here for the first part.

Last time, we discussed the basics as well as these two tactics:

  1. Translate everything and make it real
  2. Use a chart or table to organize info

Today, we’re going to dig a bit deeper into how the test writers can make translation really challenging.

Task 3: finding hidden constraints

The higher-level the problem, the more likely it will be to contain some kind of constraint that is not stated explicitly in the problem. For instance, I could tell you explicitly that x is a positive integer. Alternatively, I could tell you that x represents the number of children in a certain class. In the latter case, x is still a positive integer (at least I hope so!), even though I haven’t said so explicitly.

Here’s another example, from page 35 of our Word Problems book:

If Kelly received 1/3 more votes than Mike in a student election

If we say that M equals the number of votes case by Mike, then how would we represent the number of votes cast for Kelly?
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