MCAT Math

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I'd like to show you the power of Pattern Recognition and numerology for the MCAT!

Numerology? The mystical relationship between numbers and the physical world?? Well, not exactly! But I hope to show you that you can often make "magic" with numbers on the MCAT. If you're patient, you will learn something . . .

First some perspective: the real MCAT has reduced the number of questions that have calculations. Nonetheless, being efficient and using pattern recognition is very powerful.

For example, even with no context whatsoever, if you see 44.8 l or 11.2 l on the MCAT, your Pavlovian response should be: "I'm dealing with 2 moles (or 1/2 a mole) of a gas at STP." Without reading the question, you recognize a multiple of 22.4 l (the molar volume, Avogadro's Law). Anything times 10 to the power of 23, instantly brings to mind Avogadro's number of particles (a multiple or fraction thereof).

It does not mean that 100% of the time the answer will depend on your Pavlovian response! We are looking at trends, likelihoods that occur rather often for those minority of questions which are number based.

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Have you seen these numbers on some AAMC exams: 1.44, 1.69? Do they ring a bell? You should have memorized all squares between 1 and 15. You likely have 1 to 10 stone cold! 11 squared is 121, 12 -> 144, 13 -> 169, 14 -> 196, 15 -> 225. They choose their numbers carefully. The moment I saw 1.44 on the MCAT, I felt there would be a high likelihood that I would be required to take the square root which gives 1.2. Pattern recognition.

Given A = sq root B

Sometimes the MCAT will say, if B increases by 44%, by what % will A increase? Easy as pie! If B increases by 44%, that is the same as saying 1.44(B) and we know that root 1.44 is 1.2 which means the original sq root B = A has increased by 20%.

(Of course, it's not a math test so they won't use "A" and "B" but rather they may present a physics equation to you)

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I'm sure you already know that even if they tell you, "given g = 9.8 m/s2," you use 10 unless the answers are very close to each other.

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A little blast from the past: pi is 3.14, root 2 is 1.4, root 3 is 1.7. Don't be surprised if you need to calculate the perimeter (2 pi r) or area (pi r squared) of a circle. Be comfortable estimating the root of anything! Root 17? Well, the answer must be between 4 and 5 but closer to 4! Check the answers and don't calculate anything if there is only one answer that is between 4 and 4.5.

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Avoid decimals until you have no choice! Fractions will usually permit you to be more efficient. For huge and tiny numbers, you need to be comfy with scientific notation. And if you can hang on to variables for as long as possible, that's even better. You may be surprised how many times mass m ends up being irrelevant as it happily cancels out!

Well, that wasn't very long . . . I hope it improves your raw score by, in "MCAT-speak," a factor of 1.05 (hmm, that's a 5% bonus!).