Examples work best when they make an abstract idea visible while leaving the idea itself intact. In teaching, an effective case should suit the learner’s level, isolate a single principle, and demonstrate how it operates under realistic conditions. A classroom test can measure comprehension gains when students must explain the reasoning behind an answer instead of merely repeating a definition. Strong examples also provide enough context to show their limits, since a budgeting exercise should separate fixed costs from variable spending rather than present one outcome as universally correct. Comparing contrasting cases can then help learners transfer the underlying method to unfamiliar problems and recognize which details require a different approach.