After doing a number of OG math questions, I've noticed that I always try to approach questions from either a theoretical or algebraic viewpoint. Obviously this doesn't always work and I've noticed that a few of those really tough questions are actually pretty easy if you just plug numbers in.

But it begs the question, how do you know when plugging numbers is in the right way to answer a question?

Thanks!

Mike

One type of question in which "plugging in" values is quite helpful is when you have variable expressions in all five answer choices. These can be word problems or algebraic manipulation problems.

The plug-in technique is particularly helpful, I find, with the algebraic manipulation problems. For the harder ones, doing it purely by an algebraic approach requires lots of algebraic gymnastics and creativity. Well, under a time crunch you may not see the golden path to get to your answer in under 2 minutes. This is a great place to pick (small, different) values for the variables and to work out all of the answer choices with those values to see if you get a match.

In general, however, there are no hard, fast rules about when to plug in vs. when to solve algebraically. The more problems you do, the more you'll start to notice patterns and predict when one approach is better than another. In the end, the goal is to be able to apply multiple approaches to any one problem. That way, if you get stuck you can fall back on Plan B.

Rey