The quadrilaterals problem is a particularly rich task, applicable to in-service teachers as well as to the students they teach. The ways in which students engage in this task, the strategies they use, and the mathematics that results align well with this "MT" Focus Issue on flexible mathematical thinking. The authors offer their observations of…

The purpose of this paper examines to what extent and asking reason the fragmentation of college mathematics have attained the present development in the course of looking at the history of mathematics education. (Contains 1 table.)