Break a problem into parts you can examine

A large problem becomes easier to reason about when its parts and relationships are visible. Breaking it down does not mean making a long list of tiny tasks. It means finding a structure that reveals what needs to be learned or changed.

This lesson introduces first-principles reasoning, working backward, and simple mental models. A mental model is a simplified representation that helps us think about a situation. Its value depends on whether the simplification preserves what matters.