Cooperative learning is a teaching strategy where students work in diverse, small groups to develop their understanding of a subject. It involves positive interdependence, individual accountability, face-to-face interaction, interpersonal skills, group processing. There are formal short-term groups, informal minute-long groups, and long-term base groups. Group size works best small, around 3-5 students. Activities include Think-Pair-Share, interviews and reviews. Advantages are increased achievement, understanding between students, self-esteem, and social and study skills.