“Grasping the structure of a subject is understanding it in a way that permits many other things to be related to it meaningfully. To learn structure, in short, is to learn how things are related…. To take an example from mathematics, algebra is a way of arranging knowns and unknowns in equations so that the unknowns are made knowable. The three fundamentals involved…are commutation, distribution, and association. Once a student grasps the ideas embodied by these three fundamentals, he is in a position to recognize wherein “new” equations to be solved are not new at all. Whether the student knows the formal names of these operations is less important for transfer than whether he is able to use them.”
Excerpted from: Wiggins, Grant, and Jay McTighe. Understanding by Design. Alexandria, VA: ASCD, 1998.