Erika here with PrepScholar GMAT picking numbers to plug into quant
problems is a well-known strategy for GMAT test takers
however most test takers approach picking numbers totally wrong and end up
wasting time and confusing themselves in this video we'll help you master this key
strategy with 4 tips for how to pick smart numbers on GMAT math problems as
always if you like this video please hit the button to subscribe and feel
free to head over to our blog for even more great GMAT content links are in the
description tip number 1 know when to pick numbers if you watched our intro to
data sufficiency video you know that picking numbers is most often not our
first strategy on most problems logic and hard math are more efficient and
more likely to get us the correct number than picking numbers is however certain
types of problems lend themselves more to picking numbers than other problems
do data sufficiency in general is more suited to picking numbers than problem
solving is while problem solving questions that ask which answers must be
true or could be true are more suited to picking numbers than other problem
solving questions similarly questions of both types that
deal with certain skills are more likely to be solved with number picking
questions dealing with number properties so integers non-integers positives and
negatives primes evens and odds divisibility etc are the number one best
candidate for number picking questions dealing with exponents inequalities and
manipulating algebraic expressions are also good candidates tip number two know
your goal when picking numbers picking numbers is a risky strategy most numbers
aren't going to tell us much about the problem at hand this is why we need to
pick numbers that we think are likely to help us achieve a specific goal on data
sufficiency our goal is to prove each statement or the statements combined
insufficient to answer the question stem so on value data sufficiency questions
we want to pick one number that will give us one value and a second number
that will give us a different value on yes/no data sufficiency questions we
want to pick one number that will give us a yes and one number that will give
us a no on problem solving our goals are similar on must be true questions our
goal is to pick a number for each answer choice that will make that answer
untrue on could be true questions on the other hand our goal is to pick a
number for each answer choice that will make each answer choice true okay so how
do we determine which numbers are likely to make our statements insufficient or
our answer choices true or untrue this leads us to tip number three think about
categories of numbers most often wrong answers or insufficient statements will
work when one category of numbers is plugged in but not when another category
of numbers is plugged in for instance on this real GMAT problem if we pick any
negative number or a positive number greater than one x squared will always
be greater than one over X which makes all three options impossible however if
we instead choose a number greater than zero but less than one x squared will be
less than one over X see if you can figure out why the
correct answer is one and two in the comments so to determine if a category
will affect our answer we can pick one number from each category to test some
important categories to think about testing are positive versus negative
greater than 1 versus between 0 & 1 as well as less than negative 1 versus
between negative 1 & 0 even versus odd integer versus
non-integer multiple of X versus non-multiple of X maximum value vs. minimum
value and greater magnitude versus lesser magnitude compared to another
number in the problem tip number 4 pick easy numbers because there is no
calculator on the GMAT quant section you'll be doing all of this math in your
head or on scratch paper this means there's a lot of room for error as well
as for wasting time make the math harder to mess up and faster by using small
easy to work with numbers so if you're looking for a negative number try a
negative 1 or negative 2 if you're looking for a fraction try 1/2 or 1/3 if
you're looking for a multiple of 3 try 3 or 6 and so on and those are the four
most important tips for picking smart numbers on GMAT quant you have any
questions on what we talked about today or suggestions for future videos please
leave a comment below thanks for watching and happy GMAT math studies