This document discusses community-based learning and its approaches. It defines community-based learning as connecting what is taught in schools to the surrounding community through local institutions, history, culture, and environment. There are four main approaches: 1) Instructional connections linking classroom material to local issues, 2) Community integration bringing local experts into schools, 3) Community participation where students learn within and outside schools through participatory experiences, and 4) Citizen action where students influence or give back to the community. The document also discusses human resources available for teaching mathematics, including teachers, experts, and advanced peers. It provides examples of natural mathematical resources found in environmental phenomena like congruence, similarity, ratios, geometric shapes, and symmetry.