### Stop Careless GMAT Quant Errors

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**Here’s a careless error that any of us might make:**

x – 7 – 2x + 4 = 3x

-x – 3 = 3x

-3 = 2x

x = -1.5

Did you spot the error? If yes, give yourself a pat on the back and keep reading. If not, go back and review each step. This time, as you think through it, you can only use the terms *added*, *subtracted*, *multiplied*, and *divided*. On each line, identify which of those operations we used, and how we used it. Read more

### GMAT Sentence Correction for Native English Speakers (Part 2)

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**A few weeks ago, I wrote about making the most of your ear as a native English speaker. Here’s the short version: you already know, intuitively, a lot of the grammar that GMAT Sentence Correction tests. But the GMAT takes simple grammar errors and buries them in long, boring sentences with lots of extraneous detail. To outsmart the GMAT, simplify and visualize the sentence in your head as you read it. This will help your ear to do what it does best.**

Now let’s talk about *when *and *why *to use your ear. It’s okay to use your ear on GMAT Sentence Correction… under two conditions. Read more

### Pronoun Ambiguity on the GMAT

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**What’s the deal with pronoun ambiguity on the GMAT?**

Unfortunately, this question doesn’t have a short answer. Pronoun ambiguity is one area in which the rules of GMAT Sentence Correction are actually a little… *ambiguous*. (Sorry!) This article will describe what we know about the rules, and, more importantly, how you can use them to gain points on Sentence Correction. Read more

### GMAT Sentence Correction for Native English Speakers (Part 1)

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**If you’re a non-native English speaker who wants to excel on GMAT Sentence Correction, there are a lot of resources out there for you. (I’d recommend starting with the excellent Foundations of Verbal.) But what if you ***are* a native English speaker? **This article is especially for you.** By leveraging the skills you already have, you can take your GMAT Sentence Correction performance to the next level and improve your overall score. Read more

### Past Participles on GMAT Sentence Correction

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**Check out these two sentences:**

*The horse raced past the barn.*

*The horse raced past the barn fell.*

Believe it or not, both sentences have good grammar. But one of them makes a lot more sense than the other one! Let’s break them down and understand why. Read more

### Why Do We Care about Yes/No Data Sufficiency Questions?

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**GMAT Data Sufficiency questions can seem a little mysterious. (If you’re just getting started, or if you need a refresher, here’s a great article on the basics of Data Sufficiency.) These problems are more like logic puzzles than math questions. That makes Data Sufficiency a good opportunity for those of us who want to score well on Quant, but don’t like doing math! However, you might have some questions about Data Sufficiency as you start to understand the problem type a little better. Here’s one of them: ****why do we categorize Data Sufficiency questions into “yes/no” and “value”?** Read more

### What Your Math Teacher Didn’t Tell You About PEMDAS

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**Here’s a phrase that might bring back some memories from middle school math class: Please Excuse My Dear Aunt Sally, or PEMDAS. (If you went to school outside of the U.S., you may have learned the acronym BEDMAS or BODMAS, instead.) You use this phrase to decide what order to do mathematical operations in: Parentheses first (from inside to outside), then Exponents, then Multiplication and Division (left to right), then Addition and Subtraction (also left to right). **

PEMDAS isn’t terribly fancy stuff. It’s just a useful little tool that helps us communicate clearly—it’s what tells us, for instance, that “2x(3+4)” means something different from “2×3 + 4.” But if there’s one thing the GMAT loves, it’s making things look more complicated than they really are. Read more

### How Many GMAT Problems Do I Need to Solve?

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**That’s a good question! Do you ***really* need to solve all the GMAT problems in the *Official Guide to the GMAT* in order to score a 700? What about the other side of the issue: is it possible that there aren’t *enough* problems in the *Official Guide*? How many GMAT problems should you solve before taking the official GMAT?

Before I share my answer, let’s get some facts on the table. Read more

### What’s the Deal with Square Roots on the GMAT?

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**Here’s one of the most common math questions my students ask: “What’s up with negative numbers and square roots on the GMAT?” Luckily, the answer doesn’t involve a lot of complex rules. In this quick article, I’ll lay out the issues surrounding square roots and negative numbers, and share everything you need to know to handle them confidently. **

If you’ve been studying for a while, or if you’ve worked your way through Foundations of Math, you probably know that there’s a strange interaction between negative numbers and exponents. If you square a negative number, the result is positive. If you square a positive number, the result is also positive. Squaring a number makes the negative sign ‘go away.’ This is where the problem with square roots comes in.

Suppose you’re looking at an equation that looks like this: Read more

### Help! I Can’t Handle GMAT Probability and Combinatorics (Part 3)

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**In the previous articles in this series, we developed a critical skill for GMAT probability and combinatorics problems: ***listing out cases*. Let’s start by taking another look at the practice problem from the end of the last article. Read more