The GRE Tutor: Outfoxing the Quantitative Reasoning Section

GRE

what does the fox say 630x315 resized 600

What does the fox say? Expo-expo-expo-exponents! 

I'm going to make a bold claim: the trickiest, most fiendish section you will find on any American standardized test isn't the logic games of the LSAT or the physical sciences part of MCAT: it's the entire GRE quantitative reasoning test. Why? Because the makers of the test can only test the same knowledge that was on the SAT, but they know that almost every student has had at least three extra years to practice those math skills. And so, for those who have more or less blown off math since they started college (humanities majors, I'm looking at you), the quantitative section of the GRE is absolutely terrifying.

Beyond the mechanics of math, the GRE also asks questions in funny ways and hides answers. The writers of the GRE can manipulate a mathematical statement in a dizzying number of ways, and they might require that you do the same thing. In this blog post, I’ll teach you how to recognize and solve a type of problem that GRE test writers commonly use to trick students: exponents.

The following problem could be taken directly from a GRE. It’s a quantitative comparison question, asking whether Quantity A or Quantity B is bigger, or are they equal? Because the question deals with real numbers, we can eliminate option D (Can’t tell). 

Quantity A

Quantity B

 164  216

 

 

 

To solve this problem, I’ll (surprisingly for anyone who knows me) turn to fashion. I lack any sense of it. This disability leads to situations where I am extremely underdressed, or extremely overdressed. Simply put, I don’t have any idea what kind of target to aim for. The correlation between occasion and outfit eludes me and so I don’t know how to look for an occasion. In my years as a GRE tutor, I've learned that students that struggle with GRE math may not recognize it, but they suffer from the same dilemma, but in a slightly different form. Instead of making sure that the clothes fit the occasion, a test-taker needs to make sure that the numbers fit the answer choices. 

 

At first, quantity A and Quantity B look very different. But, by massaging one of the quantities to look like the other one, this problem becomes solvable. A good GRE test taker realizes that a good strategy is to simply make her numbers look like the GRE’s numbers.

Practically, this means fiddling around with numbers. Because it’s an exponent question, I would guess that the GRE wants to test my knowledge of exponents. With the knowledge that I want to make Quantity A look like Quantity B, I start tinkering:

  1. My end goal is to rewrite 164 using only 2’s and exponents.

  2. 164 could be rewritten as (42)4 or 48.

  3. If I apply that process of rewriting again, I get 4=22 so 48= (22)8.

  4. Applying exponent rules, I see that (22)8, is equal to quantity B.

  5. Therefore, the answer is C: the two values are equal.

Math needs some kind of target. Let the answer choices on a standardized test guide you towards the right answer or what the right answer should look like. 

Sign up to receive a free, 8-part GRE Math Toolkit

Comments

topicTopics
academics study skills MCAT medical school admissions SAT expository writing college admissions English MD/PhD admissions strategy writing LSAT GMAT GRE physics chemistry math biology graduate admissions academic advice ACT interview prep law school admissions test anxiety language learning premed MBA admissions career advice personal statements homework help AP exams creative writing MD study schedules test prep computer science Common Application summer activities history mathematics philosophy organic chemistry secondary applications economics supplements research 1L PSAT admissions coaching grammar law psychology statistics & probability legal studies ESL CARS SSAT covid-19 dental admissions logic games reading comprehension engineering USMLE calculus PhD admissions Spanish mentorship parents Latin biochemistry case coaching verbal reasoning DAT English literature STEM excel medical school political science skills AMCAS French Linguistics MBA coursework Tutoring Approaches academic integrity chinese letters of recommendation Anki DO Social Advocacy admissions advice algebra art history artificial intelligence astrophysics business cell biology classics diversity statement gap year genetics geometry kinematics linear algebra mechanical engineering mental health presentations quantitative reasoning study abroad technical interviews time management work and activities 2L DMD IB exams ISEE MD/PhD programs Sentence Correction adjusting to college algorithms amino acids analysis essay athletics business skills careers cold emails data science dental school finance first generation student functions graphing information sessions international students internships logic networking poetry resume revising science social sciences software engineering tech industry trigonometry writer's block 3L AAMC Academic Interest EMT FlexMed Fourier Series Greek Health Professional Shortage Area Italian Lagrange multipliers London MD vs PhD MMI Montessori National Health Service Corps Pythagorean Theorem Python Shakespeare Step 2 TMDSAS Taylor Series Truss Analysis Zoom acids and bases active learning architecture argumentative writing art art and design schools art portfolios bacteriology bibliographies biomedicine brain teaser campus visits cantonese capacitors capital markets central limit theorem centrifugal force chemical engineering chess chromatography class participation climate change clinical experience community service constitutional law consulting cover letters curriculum dementia demonstrated interest dimensional analysis distance learning econometrics electric engineering electricity and magnetism escape velocity evolution executive function freewriting genomics harmonics health policy history of medicine history of science hybrid vehicles hydrophobic effect ideal gas law immunology induction infinite institutional actions integrated reasoning intermolecular forces intern investing investment banking lab reports linear maps mandarin chinese matrices mba medical physics meiosis microeconomics mitosis mnemonics music music theory nervous system neurology neuroscience object-oriented programming office hours operating systems