The document discusses three approaches to curriculum design: subject-centered, learner-centered, and problem-centered. The subject-centered approach focuses on teaching academic subjects. The learner-centered approach places the learner at the center of the educational process and builds the curriculum based on their skills and knowledge. The problem-centered approach assumes learners experience problems in living and develops the curriculum to help them solve problems and become independent problem-solvers. Each approach has its own principles that guide the curriculum design.