In this video, Jess and Rich talk about “testing cases” in Data Sufficiency problems — i.e. coming up with example numbers and trying them out to see what happens. The goal of this strategy is to help you determine if the DS question prompt is always, sometimes, or never true. As Jess explains, the key with testing cases is to choose different numbers with different properties that still fit the constraints of the prompt, in order to see if they produce varying outcomes. If they do, then the statement is insufficient!
Check out the video for more on this important strategy and to try out a sample problem on your own.
Eager for more DS help? Check out the other installments of this Quantitative Strategy lesson!