A good Python educational resource regarding complex numbers: http://www.lightandmatter.com/complex.pdf The complex built_in is not really used in this brief tutorial. Instead the student is guided toward building their own complex 'primitive' using a 2 element list [real,imag], and building their own complex arithmetic functions. More generally, I see the authors approach as a good example of how a little Python understanding can be leveraged to 'add value' to a curricula - over a wide range of subject matters. As it happens, I had decided to roll my own Complex class as a classic Python class for my purposes. Deriving from 'complex' as a new style class turns out to have some, well, complexities - and at the moment there doesn't seem to be a lot of sample code and tutorials out there on the subject. Concluded I am in no position to be a pioneer. More sample code of this kind will, I'm sure, eventually make its way into circulation. Art