When it comes to the math section of the SAT or ACT, it’s easy to get overwhelmed by complex or confusing questions. Luckily, even if you find yourself truly struggling with a difficult question, there’s a helpful last-ditch technique that can still get you the right answer.

Allow us to introduce your new secret weapon: “Plug in Numbers,” or “PIN.” PIN is a great way to turn an algebraic problem on its head. Remember, one of your biggest advantages on these exams is that most questions are multiple choice. The PIN technique can be used to leverage the answers provided to your benefit. This works particularly well on these exams because no one is checking your work or critiquing how you answer a question — you get the points for the correct answer no matter how you arrived there.

The basic idea of PIN is to plug in your own numbers in place of variables or unknowns to solve questions. Often, this can work for both algebra and geometry questions. These questions are often asking about relationships between numbers, and those relationships will stay the same, no matter what the numbers are. That’s why, as long as you follow the rules of the questions, you can answer them by plugging in your own numbers.

Here’s an example of how you can solve a problem using PIN:

problem1

Let’s begin by assuming we have no idea how to solve this question. Using PIN, let’s plug in a number for t to help figure out  this problem. We know that t has to be greater than 1, so let’s try something simple like 3.

If t=3, then the question is asking “If 3 is a number greater than 1, then 3^2 (or 9) is how much greater than 3?” Simplify even further and the question is asking, “9 is how much more than 3?” This is much easier to understand than the original question, isn’t it? We can clearly see the answer is 6.

Now, we can take what we’ve found and test it against the answers. Which one comes out to 6?

The first three answers can all be eliminated immediately because they are too small (1,2 and 3), which leaves us with just D and E.

Plugging in our numbers to D, we have 3(3-1), which simplifies to 3(2) and solves for 6.

So answer D is correct, but let’s solve answer E too, just to be sure D is our only correct answer.

Plugging in our numbers to E, we have (3-1)(3+1), which simplifies to (2)(4) and solves for 8.

This doesn’t work, which means that D is our answer!

More PIN Considerations

As another “PIN” tip, when deciding which numbers to test, consider including irregular numbers, such as 0 and/or a negative number.  In this example, those numbers would not have held true with the statement in the question, but in other cases, they may be extra helpful in allowing us to see the right answer.  

If you intend to use PIN on an exam, make sure that you’re confident in your understanding of this tool. Be warned: PIN can sometimes take a bit of time, so also make sure you’ve got an eye on that clock. Sometimes, when you start to use PIN, you’ll see that one or more of the answers is immediately incorrect. Take a few moments to strike out these obviously incorrect answers! It may seem trivial, but any time saved can really help in the end.

Also, if you’ve completed your math section and find that you still have some time, PIN is a great way to double check your answers or return to questions you skipped initially. It’s always smart to double check an answer using a different method than what you used to solve the problem originally, to ensure that you’ve actually solved it correctly.  This can help you avoid making the same mistake multiple times and, as a result, getting the same incorrect answer.

Extra PIN Practice

Think you’ve mastered the PIN technique? Here are some sample questions that you can practice your skills on! Good luck!

problem2

problem3problem4
(Answers: A, B, K)

So, how did  you do? Have you mastered the PIN technique? If so, stay tuned for the next SAT/ACT blog post coming soon.

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