Finding patterns in exponent problems on the GRE Quantitative section

graduate admissions Graduate School GRE MBA admissions quantitative reasoning
By Sean

Title_ How to Study Efficiently for Hours On End (With the Help of a Tomato) (5)One thing about GRE quant questions and standardized test math questions more broadly: if a question seems impossible or like it will take a ridiculously long amount of time to complete… It isn’t as difficult as it seems! Let’s dive right into a practice problem to see an example. Take the following numeric entry problem:

Screen Shot 2020-10-01 at 9.08.03 AM
Screen Shot 2020-10-01 at 9.08.41 AM

Let’s take a step back. So far, we have the following:

Screen Shot 2020-10-01 at 9.09.54 AM

Notice anything? I think we may have a pattern of 7, 9, 3, 1, repeat. But let’s just calculate out another three digits to be sure.

Screen Shot 2020-10-01 at 9.10.44 AM

Yup, the pattern checks out! (Note: For future reference, units digit patterns for exponents come in cycles of at most four, so once you reach the fourth number you can stop and leverage the pattern you have found rather than wasting precious time on superfluous calculations. A caveat to this is that these patterns could also be LESS than four…)

Screen Shot 2020-10-01 at 9.11.40 AM
Screen Shot 2020-10-01 at 9.12.19 AM

So, how can this methodology be applied to different variations of GRE problems? As you can expect, the wording and style of the problems can vary considerably, but often the core approach taken to solve the question can be similar. Consider the following “select one or more answers” multiple choice question.

Screen Shot 2020-10-01 at 9.20.48 AM

Now, before reading this post you may have wasted your time trying to carry out many calculations, hoping you got all the right digits. But, now that you are familiar with finding patterns in exponent cycles, this should be a breeze! n must be a positive integer, so let’s start with 1 and go from there.

Screen Shot 2020-10-01 at 9.14.37 AM

Let’s try one more, this time a quantitative comparison question.

Screen Shot 2020-10-02 at 8.24.33 AM
 
So, what is this question really asking? Something pretty similar to the last one, and the one before it, in a slightly different way! We are trying to find a pattern in the exponent cycle for 824.
 
Screen Shot 2020-10-01 at 9.16.21 AM

It looks like the pattern alternates between 6 and 4; it is 6, 4, repeat. Thus, there are only two possible values of the units digit for 𝑁. Meaning the value of Quantity A is 2. This means that Quantity B is greater, which is (B).

In conclusion: When you first see certain GRE quant problems, they can look completely foreign, or seem impossible. But with proper preparation, you can equip yourself with the key skills necessary to tackle those problems with ease. You can work your way through the different wordings and styles the test makers throw at you by leveraging a fairly low number of core competencies while also looking for patterns to find solutions more quickly.

 

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

Related Content