hi i'm erika one of the senior curriculum managers here at magoosh and a gmat expert
now i've said it before and i'll say it again what makes a gmat math question higher difficulty or at
a higher level is the question's complexity not its subject matter so that means that a question
on any topic can be 400 level or 700 level check out my video on the hardest and easiest gmat math
questions for more on this and a breakdown of some example problems that have the same question topic
but wildly different difficulties now that said what makes a question a higher difficulty or a
higher level isn't necessarily what makes it hard for test takers there are certain concepts that
most test takers really struggle with regardless of the level of the question now this is really
bad for their scores because they're missing easy questions on that topic because for them
those easy questions are actually really hard in this video we're gonna break down six of the
hardest gmat math concepts that you're likely to encounter on test day now stay tuned for the
end because the last one is likely to surprise you so the first hardest gmat math concept is
combinatorics and this is actually kind of a two in one because combinatorics encompasses
both permutations and combinations and therein lies the challenge because not only do we have
to memorize two different formulas two different approaches but we also have to be able to identify
within a problem which one we have so is this a permutation with the permutations formula with a
permutations approach or is this combinations with a combination formula and a combinations approach
now that's challenging in and of itself but there is also more challenge because there are
kind of fancy things that we can do with combinatorics that make them more challenging
so we can bring in restrictions we can bring in things like at least problems that can take
something that's already pretty difficult because of all the memorization and understanding that has
to go into it and make it even more challenging the second hardest gmat math concept is pretty
related to the first and its probability and part of the reason that probability is related
to combinatorics is that a lot of probability problems actually rely on combinatorics in order
to figure out totals and subtotals so that makes these problems challenging in that they involve
a challenging question type within them but they also have other elements of complexity so again
at least problems show up in probability there are things like binomial probability which has its own
formula now if you're curious specifically about at least problems on permutations combinations
and probability check out my video on the topic with a fun trick for how to handle them
the third hardest gmat math concept is overlapping sets which is a classic gmat word problem type and
it comes in two flavors so there is the matrix box overlapping set which is commonly what we're gonna
use for uh two overlapping sets but there's also the venn diagram overlapping set which can be used
for two overlapping sets but i more frequently use it for three overlapping sets now these are
tricky enough on their own because the best way of handling them is with one of these types of
diagrams so we have to be familiar with how to use them effectively in the common traps that
come with labeling them incorrectly and filling in information in the wrong place but they can be
even more complex when we do things like bringing in real numbers mixed with things like percents
or ratios or variables so the fourth hardest gmat math problem type is work rate and this is another
classic word problem type on the gmat it is a subset of the larger category of rate problems
now work rate problems have their own formula which make things a little bit more challenging
because once again there is some memorization involved here and some familiarity that we need
going into these problems but once again they can be made even more complex so applying that formula
in multiple ways to account for things like starts and stops in a scenario driven word problem
now if you struggle with word problems like overlapping sets and work rate let me know in
the comments if you'd like a video breaking down those particular word problem types along with
some of my other favorite word problems the fifth hardest gmat math problem concept is statistics
now not all statistics questions are particularly challenging a lot of the statistical definitions
are things that people are comfortable with and familiar with however there are some that are less
familiar like standard deviation and there are applications of even the easier statistics or more
familiar statistics that can be challenging for a lot of test takers so a lot of test takers don't
know how to handle things like weighted average or dealing with sets with consecutive integers
or again scenario driven word problems like min max problems so again these can be challenging
because test takers lack familiarity with the different applications and the sixth hardest
gmat math problem concept is integer properties now this is surprising for a lot of test takers
because this is an arithmetic concept it's addition subtraction multiplication division
and that seems like it should be easy enough to execute on however most of these problems
are going to be more conceptual they're not going to be about executing on these operations they're
going to be about understanding these operations so there'll be things like definitions around
factoring and divisibility and remainders etc etc and the problems will often deal with numbers
that are too large to calculate so things like exponents and factorials will force us
instead of actually doing the operations to understand them and apply what we know about them
so these are challenging for a lot of test takers because they are surprising and test takers go in
unprepared for them because they don't know that they're going to be this challenging and those are
six of the hardest gmat math concepts now there are definitely more but these are some of the most
inaccessible the test takers because of how hard they are to guess on without a solid foundation
and understanding of the content now these are all likely to come up at least once
on your test day so be sure to incorporate them into your study so you aren't stumped
let us know if this video helped you by liking and subscribe for more videos from me and the
other experts here at magoosh and if you have any questions or comments or suggestions for
future videos leave them in the comments below thanks for watching and i'll talk to you soon