Can you quickly calculate 15% of 42 in your head? In this lesson, we’ll examine a fast way to perform this calculation and others.
The technique I’ll demonstrate is based on the fact that it's incredibly easy to find 10% of any value,...

The following is a metaphor for how students often respond to a particularly tough GMAT question:
It’s a dark, moonless night, and you find yourself alone in a haunted house. Blood drips from the ceiling, and the words “Get out!” echo...

In my last article, we examined the importance of considering mathematical strategies other than those we learned in school. So, rather than approach a question as though our former teachers will be checking (and grading!!) every detail of...

The good news: the GMAT Quantitative section tests concepts that you already learned in school. The bad news: if you insist on always solving GMAT math questions using the same techniques you learned in school, you’ll likely score lower...

After reading a few solutions in various GMAT Data Sufficiency forums, one notices that sometimes people plug in values to test sufficiency, and sometimes they use a different (often algebraic) approach. So, how do we identify those times...

In a recent article, I discussed my concern regarding the term “permutation.” In this article, I’ll discuss my concern regarding the question, “Does order matter?” People often use this question to help determine whether to use...

In my previous article, I mentioned that the Fundamental Counting Principle (FCP) can be used to solve most GMAT counting questions. The FCP says:
If a task can be completed in stages, where one stage can be accomplished in A ways,...

I’ve never been a big fan of the phrase “Combinations and Permutations.” It suggests that all counting questions can be solved using either combinations or permutations, when this is not so. Compounding the problem is an infamous rule that...

Most GMAT students don’t spend enough time considering the mindset they’ll need on test day. In my very first article, I suggested that the simple act of smiling can increase your performance. In this article, we’ll go a little deeper and...

To set up this article, please consider a forum post from some fictitious wrestling forum:
The state wrestling tournament is 1 month away, and I want to win the 184-pound weight class. To lose enough weight to qualify for that weight class...