HP-22S
The HP-22S is anstelectronic calculator from the Hewlett-Packard company which is algebraic and scientific. This calculator is comparable to the HP-32S. A solver was included instead of programming, but it was very well implemented. It suffered from the same constraints as the 32S since it lacked enough RAM for serious use, however it is still a very good calculator with a good feature set. Functions available include TVM and unit conversions. Only single letter variable names are allowed, but with somewhat less than 1/2 K of RAM, this is not a serious issue.