15 apples is 75% of 20 apples. 15 is the part, 20 is the whole, and 75 is the percent.
Work Step by Step
Make an example such as this one where you define a whole group of things, part of that group, and what percent of the whole group the part makes up. Here, 20 apples is the whole group and 15 apples is part of that group. 75% defines the portion of the whole that 15 apples makes up.