1. University of Illinois at Chicago, 1040 W. Harrison St., Chicago, IL 60607;
. His research interests include constructivist theory and mathematical cognition.MARIA VARELAS is an associate professor in the College of Education (M/C 147), University of Illinois at Chicago, 1040 W. Harrison St. Chicago, Il 60607;
. Her research interests include constructivist approaches to teaching and learning and science education