While quite appropriate for a hand held device, the
bunch-o-buttons interface provided by a typical calculator is
ridiculous when implemented on a computer screen. Instead, THX-1138
provides an approximation to electronic paper. As you enter the
expression, it is displayed the way you would write it on paper,
and you can edit it directly.
You can also plot functions and print the graphs as PostScript,
and there is a window for base conversions. (e.g. hex to
The binary and source distributions can be downloaded from:
THX-1138 is free.