In order to provide high school students with general problem-solving skills, two LOGO computer-assisted instruction units were developed--one on the methods and strategies for solution and a second on the relation between formal and informal representations of problems. In both cases specific problem contexts were used to give definition and articulation to central notions like problem, problem form, solution method, and optimal strategy. The unit on strategies in problem solving illustrates strategy formation in two contexts--extrapolating number sequences and exploring mazes. The unit on story problems in algebra attempts to help students learn to convert a story problem into formal mathematical terms. For more information about the LOGO project, see volumes I, II, and IV of the report (EM 009 419, EM 009 420, and EM 009 422). (JY)