Calculating percent change and percent difference

Percent change and percent difference are very similar concepts, but they have slightly different equations. In the exam, you will be expected to not only be able to calculate each but also understand when to use each. Be careful, the exam may have the correct answers to both equations as possible choices, so you can’t just calculate both and see which is on the list of answers.

Percent change

When thinking about percent change, the word you need to focus on is change. The idea is straightforward; you are concerned with how a single value has changed from point A to point B. You are just reporting this change as a percent, in reference to the starting value. When we say “in reference to a starting value,” we are trying to communicate that the starting value is the star of the show. It is subjective; all of this is told in terms of the starting value. Does the value increase or decrease since the starting value...