Using Clairaut's historic-dynamic approach and dynamic geometry tools in middle school can develop students' conceptual understanding before they encounter formal proof in geometry.
Hyewon Chang, email@example.com, is an associate professor at Seoul National University of Education in South Korea. She participated in developing current national curriculum for mathematics and is interested in research on learning geometry and using history of mathematics for mathematics education.
Barbara J. Reys, firstname.lastname@example.org, is Curator's Professor and the Lois Knowles Faculty Fellow at the University of Missouri- Columbia. She directs the Center for the Study of Mathematics Curriculum, focusing on improving mathematics education through research and development efforts related to mathematics curriculum.