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)

Analyzed are the different stages in the conceptual evolution of infinity as developed historically through the work of Bolzano and Cantor. Results of a study of 18 to 20 year old's concept of infinity prior to instruction produced aspects of the passage between conceptual levels of infinity. (MDH)

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)