The only issue I see with plugging in numbers is that it may be a time consuming process, since you will have to test out 4 scenarios in most cases: a small positive integer, a large positive integer, a small negative integer and a large negative integer. In some cases, fractions might have to be tested too.

Yes, every strategy has its benefits and drawbacks. However, if the question is talking about students in a class, you will not need to test negative integers or fractions. It takes some practice to use the plugging numbers strategy efficiently and ETS knows that we know this strategy too so they try to make it less obvious that it can be utilized or they make it harder. But it is very useful with questions about the sizes of fences, money, and other such questions where you can pick a single number for each variable since you will have a single sum/product/etc.

Some questions esp algebra-heavy questions, this strategy is helpful, esp if it is complicated equations that would otherwise take a bunch of time and potentially result into errors. My suggestion is to be prepared to test positive/negative (and if setup allows a zero) and also fractions, esp if there is multiplication or exponents and be especially careful if this is an inequality.

Also, keep in mind that 1 is almost always a BAD number to test for. Zero is usually a poor number as well.

Why zero and one poor ?

I'm guessing here but one of the reasons is the unique characteristics that both numbers have.

Please answer if u are guessing.
1 and zero considered a smart numbers

Posted from my mobile device

It depends on the question in front of you

zero is pooer because is neither positive or negative and it is even. So it could bring you false positive result.

You always should try the following

2,1, 1/2,0,-1/2,-1,-2 at the very least

Anything but smart for plug-in answers strategy.

You will realize the inconvenience of picking 1 or esp 0 when you actually try to solve one of the questions using the Plug-In-Numbers strategy. Here is an example of an easy question:


Derek can read x pages in 5 minutes. At this rate, how long will it take him to read p pages?

A. 5p/x
B. 5x/p
C. p/(5x)
D. 5/(px)
E. px/5

If you plug 0 for P or X, you will end up with at least 1-2 answers udefined as you cannot divide by 0 ... at least on the GRE


P.S. Best numbers would be uniquely divisible. In this case you can pick 3 and 6. Thus 3 Pages in 5 mins, so how long will it take him to read 6 pages? Should be 10 mins. I specifically did not pick 5 or 10 (I don't want any number to be the same including the answer). I want all my numbers to be unique. You can probably also use larger numbers such as 10 and 40 or something along those lines - i sometimes do that when I want the result to be clearly BIG so that any division will immediately indicate it is incorrect which means I actually don't have to do the operation, and save time. I also like 3 since it is not divisible by 5 or 2 which is what I am building into my model, so it reduces the possibility of multiple matches. This is something you learn through experience