Conclusion
The issues that interested us most when viewing this pre-and-post data were students’
perceived legitimacy of complex numbers, as demonstrated by the parabola problem and
students’ responses to whether or not complex numbers are really numbers; the changes over the
course of instruction in students’ ability to think of complex number as a single thing rather than
a pair of things; and the apparent ease with which students found a way to use the complex plane
in order to represent addition of complex numbers geometrically.