# GMAT & MBA Admissions Blog

While I’d describe myself as above average at math, when I was preparing for the GMAT, I realized two things:

1. I hadn’t taken a pure “math class” in a long time and...
2. I’ve never been good at mental math.

### Context: My Math Background and GMAT Quant Score

First, a little context on my background – which I think many GMAT test takers might relate to.

In high school, I was in the advanced math classes, including Calculus. I took the ACT a few times, and if I can remember that far back, my ACT-Math score was above the 90th percentile every time – sometimes much higher.  In college, I majored in Finance, which required a lot of math.   After college, I became a business strategy consultant, and built lots of extremely advanced financial valuation models, and gained tons of valuable experience debating arcane and complex valuation principles – which again, involve a lot of math.

All in all, if you’d asked me whether I was “good at math” I would have said yes.

But, I hadn’t really taken a pure math class in over 6 years.   Also, for whatever reason, doing relatively simple math quickly in front of colleagues, or even figuring out a tip at a restaurant in front of friends, always made me nervous.  I struggled with mental math.

And sure enough, my GMAT math score was lower than I was hoping for.  I ended up scoring very well on verbal, but in only the 75th percentile on Quant.  I ultimately was able to get into Kellogg, which is at least one data point that violates the 80/80 rule (i.e., a rule of thumb many people believe in, which suggests that top MBA programs want to see both Quant and Verbal scores above the 80th percentile).

So, based on this experience, this post offers a two part strategy for improving your GMAT quant score:

1. Focus on Building Understanding of Key GMAT Quant Concepts – In this post, I’ll urge you to clearly identify and be realistic about the difficult math concepts you don’t fully remember or understand, and use your GMAT prep time learning or re-learning these concepts, not just doing  practicing problems.
2. Improve Your Mental Math Skills – In my next post, I’ll address the importance of mental math on the GMAT and provide some easy-to-implement ideas and tips for improving your mental math skills.

The ideas in these posts come from both my reflections on how I could have improved my own personal GMAT score and many discussions with expert GMAT tutors as I’ve built MyGuru over the past several years.

### Idea #1 - Focus on Really Understanding Difficult (and sometimes new) Concepts

The GMAT tests math concepts and skills you may not have been exposed to for a while: Algebra, Geometry, Trig, Statistics, world problems, etc.    For example, I took Calculus in high school, effectively testing out of all but a few math classes in college.  So, I hadn’t taken that much pure math in a while, even though my job was very quantitative.

It’s obviously critical to review all of these math areas (i.e., you’ll need to know the rules of exponents and all about angles of triangles on the GMAT), as well as become comfortable with data sufficiency and integrated reasoning question types.  So, there’s just a general point to be made about reviewing all of the relevant concepts, re-familiarizing and refreshing yourself.

However, there were a few concepts which, although I would sometimes muddle through and answer questions correctly, deep down I could have told myself I didn’t fully understand.

When you get a problem wrong, it’s natural to review the correct answer, and use the explanation provided as a way to learn how to do the problem.  However, this sometimes leads to a superficial level understanding of any given concept. With the right set up, you  might start to get a good portion of that question type correct moving forward, but on test day you may not fare so well if the question is worded differently, etc.

For example, I always had trouble with the GMAT questions that involved counting the ways that a group could be organized.  I went through my entire GMAT prep process without really nailing those concepts, or even knowing the official name for the concepts that those questions tested.  But, I did a bunch of practice problems, and had convinced myself that I was good to go when/if questions of that nature were asked.

Years later, I asked one of MyGuru’s most senior GMAT tutors to write a few GMAT blog posts for us, and he chose a topic called - Combinatorics.  He chose this topic because, as he says in the post,

“This is an introductory post on combinatorics - the art of counting. Combinatorics is one of the most difficult parts of the GMAT because it is not part of the standard American high school curriculum. With many other troubling types of problems, such as rate questions, fraction / decimal / percent problems, etc., a bit of review and a lot of practice will do the trick, but, in general, to get a handle on combinatorics problems students have to learn something new.”

Most of GMAT Quant topics were concepts I fundamentally understood well after some review, because I had previously learned them, but not this one.  I fumbled through learning Combinatorics on my own.

Here are four “hints” that you don’t truly understand any given topic on the GMAT:

1. Obviously, if you get most of the questions of any given type wrong, that’s a strong signal.  Even if you think the errors are silly, if you consistently miss one type of question, there’s a problem with your core understanding.
2. You get some, or even most, of the questions of any given type right, but when the question is worded differently, you’ll mess up
3. You’d have trouble explaining the concept to a friend
4. You’d never been exposed to it before studying for the GMAT (e.g., Combinatorics for most people, Probability for some people, etc.)

I also just think that most of us have an intuitive sense for when we only understanding something on a superficial level.  You just need to be honest with yourself.  The stress of taking the GMAT in real-time in a testing center will generally cause you to miss any relatively difficult question that tests a concept about which you aren’t very confident.  Don’t say to yourself, as I did, that you’ll “figure it out on test day if I happen to get a question like this.”

In our experience, here are the GMAT Quant concepts that many students struggle with, since they may never have learned the concepts in school.  These can account for about 20% of the questions on the GMAT.

• Number theory – understanding primes, squares, etc.
• Combinatorics – the art of counting
• Probability – what is the chance x will happen given y and z?
• Rates – questions about movement, time, distance, etc.

In my next post, I’ll address the importance of Mental Math and provide some tips and ideas for improving your mental math skills.