Presents an inquiry into students' conceptual development of a graphics calculator function for direction. Discusses reflective thinking and reflective enculturation, operational and structural understanding, and situated abstraction. (Contains 33 references.) (Author/ASK)

We find that students in the big mathematics service courses at the Johns Hopkins University who were encouraged to use calculators in K-12 have somewhat lower grades than those who weren't.

The importance of teaching computational estimation is discussed, with note of its increased significance because of widespread use of calculators and the need to develop number sense. The reason for its failure to be taught is traced to the multiplicity of methods, and some detailed suggestions are therefore presented. (MNS)