As it turns out, economists, chemists, aviators, and scuba divers use the Rule of Three (even Agatha Christie did when she wrote a series of plays entitled The Rule of Three). Although it has not been labelled as the Rule of Three, great educators have used it in classrooms since Aristotle (ever heard of syllogisms?). So what is the Rule of Three for learning? Well it is as simple as one, two, three (not kidding). The Rule of Three for learning basically establishes the requirement that students be given the opportunity to learn something at least three times before they are expected to know it and apply it.
Read the full post by Ben Johnson here: Using the Rule of Three for Learning | Edutopia