Repetition and Examples People learn through repetition. No idea or fact is completely understood the first time it is seen. For complete understanding, the idea should be shown in a variety of contexts and applications, and should be connected to as many previously learned concepts as possible. One way to provide repetition is through examples. The first examples should be easy, to make sure students grasp the idea completely and to provide confidence.
More advanced examples can show the use of the idea in different contexts.
When possible, examples should be spread out over multiple class periods so students have time to digest the material and generate questions. Many new ideas are, initially, simple and straightforward. When this is the case, introduce the idea so that students can see it is simple. Then add complexity incrementally, occasionally reminding students that the original idea was simple. Hashing is fundamentally simple, but it has expanded to the point that it is now reserved until the junior or senior level.