Cooperative learning methods capitalize on the heterogeneous student bodies of most urban schools. They appear to foster better student achievement than individualistic methods, to increase cross-ethnic friendships, and to improve students' self-esteem and positive attitudes toward other students and the school. Six currently published cooperative learning techniques are: Student Teams-Achievement Divisions, in which students in four-member heterogeneous teams take individual quizzes and receive a team score based on the degree to which each student improved; Teams-Games-Tournament, in which learning teams compete and individual scores contribute to a team score; Teams-Assisted Individualization, in which teams are rewarded on the basis of math units mastered by all team members; Jigsaw I and II, in which individual students become experts on particular sections of a lesson and proceed to teach their teammates; Learning Together, in which students work in small heterogeneous groups to complete a common worksheet; and Group Investigation, in which groups choose subtopics from a class unit and further break their subtopics into individual tasks to prepare a group report to the class. (ETS)