I find that I'm using my orginal Poqet PQ0181 computer lots as a calculator sitting on the design bench. I'm doing tons of "oscillator analyses" lately on the Atlanticon Kit called the "Snap" ( one transistor transmitter kit for all Atlanticon attendees) ... bias calculations, load impedance matching, torid windings, component reactances, etc.
The Poquet works great for this purpose, but it only has a basic 4-function calculator (+, -, *, /). And the PC Plus doesn't even have this built-in calculator.
I recently asked if anyone had a favorite DOS calculator program from days gone by that does more functions (memory, exponents, logs, etc), and a bunch replied. The best perhaps was Ron WB3AAL who responded with the mega-link page of DOS programs, sorted for "calculator" ( http://www.cyfronet.krakow.pl/ftp/simtel/simtel_calculte.html ) I pulled the first one that looked interesting and it worked *maaaaavelously*!! It's a scientific function calculator program called "balicalc" and you can get it at that site. Poke around ... you might find some others that you like better. (I didn't have time to explore much.)
Another thing that I find *really* useful having on the Poqet is the "Hamcalc" bunch of programs for calculating pi-filter components, toroid windings, resistive pad values, and so on. This is *very* convenient to have at my fingertips, as opposed to sliding back and forth to the laptop on the other side of the room for the same progam access. Many of the programs in this VE3ERP collection of ham radio computation utilities are BASIC programs. You need to run GWBASIC and then run the <filename>.bas utility program that you want ... GWBASIC works great! And it comes in the shareware Hamcalc. You can get Hamcalc from the http://oak.oakland.edu:8080/pub/hamradio/arrl/bbs/programs archives. (You might need to use an FTP program when getting this, depending on your browser's ability to retrieve files from FTP sites.)
I'll tell you, I'm loving these Poqet PCs for the QRP workbench!
73, George N2APB