Naïve theory is deeply rooted in society. When implementing redistribution policies, such zero-sum ideas can be an obstacle. To help discredit this belief, in this paper, a civics lesson plan is recommended to help students realize the mechanisms of specialization and exchange using comparative advantage as a teaching material. Practicing this lesson plan has shown that it is possible for third-grade junior high school students to reconsider the zero-sum idea through comparative advantage, and think about social fairness based on theory.