Suppose the last time you saw math was way back in high school. You took just enough to get into college, and then promptly ran away from the Dragon in terror. Now, alas! You have to face the GMAT, and — Heavens to Murgatroyd! —- that same GMAT expects you know how to do a whole truckload of math! How are you going to get in shape?
Well, the first uncomfortable truth is that the best way to rebuild once-existent (or never existent!) math skills is practice, practice, practice. Just resolve that, starting right now, you are going to do at least half an hour of GMAT math practice every day. Math is not a spectator sport, so there’s no substitute for the hard work of doing it yourself. Don’t be afraid of making tons of mistakes in the early stages. Make the mistakes, then learn from your mistakes: this is a non-negotiable part of the process of learning math. The mark of a truly excellent student is: never make the same mistake twice.
Anyone preparing for the GMAT should own a new copy of the GMAT Official Guide. Toward the front of this OG, there’s a 40-page section entitled the “Math Review”. This section lists all the individual math facts and math areas for which you are responsible. That’s good for getting a sense of the lay of the land, and in particular, it’s very good at the start for seeing topics that make you think: “Gadzooks! I haven’t seen that in donkey years!” Beware, though, of the limitations of the OG Math Review —- even if you memorized that entire section word-for-word (an exercise I do not recommend!), you would not thereby “know” math. The math is not in the static math factoids, but in the doing itself.
For example, for GMAT work rate problems, it’s essential to know the formula W = RT, (work done) = (rate)*(time). That formula, though, is just “square one” in understanding the topic. The GMAT is NOT going to give you, say, a rate and time and ask you to find the work done. Rather, they are going to give you two people or machines working side-by-side at different rates, or something that works at one rate under one set of conditions and at a different rate under another. The GMAT will always push you beyond the simple equation to the rigorous critical thinking.
Many areas of math, in addition to the individual factoids, also involve developing a perspective, a framework. For example, GMAT probability questions are particularly tricky, because there’s a very subtle worldview needed to understand them — a worldview that absolutely flies in the face of a culture in which people optimistically buy lottery tickets and expect zero health consequences from cigarette smoking.
Any good GMAT prep resource will provide a ton of practice problems, teach you the requisite math facts, and give you useful strategies for problem-solving. Those strategies are at least as important to learn as the individual math facts. Strategies such as estimation, backsolving, and the intelligent picking of numbers are crucially important.
As you may be aware, you must perform the GMAT Quantitative section without dint of a calculator. This fact places on you the onus of practicing mental math, every single day. Every day, over and above any GMAT practice, you need to add, subtract, multiply, and divide in your head. For example, you need to know your “times table” cold. Practice real world math reasoning —- running grocery bills, gas mileage of your car, square feet of a room, etc. When you see a random two-digit odd number — say, the last two digits of a license plate or phone number) — figure out whether that number is prime. Train to be a mental math superstar!
I believe folks at the outset often overestimate how hard the GMAT is. Math can seem unforgiving because there is often no gray area — there’s just absolutely right and absolutely wrong, and folks who are rusty land on the latter side most of the time. That can feel intimidating. Math, though, is fundamentally logic. If you can think logically and keep details organized, that’s more than half the battle right there. With some focused practice, you can make sense of math on the GMAT!