The thought processes of 507 elementary, secondary, and university students engaged in problem-solving situations are examined in this study. Results indicated that pupils who got correct answers often showed incorrect reasoning justifications. No significant sex differences were indicated. (MP)

Asserts that college students lack understanding of the concept of function. Based on an epistemological theory, offers an instructional treatment using computers that presents a process concept of function and results in substantial improvements in student understanding for many students. (29 references) (MDH)