The sad thing is that I know, from having done enough tutoring, that RPN-type calculators can be much better tools in teaching than the textbook-input-output style one like the Casio FX-991. I also do not consider programming on the level of the HP15 problematic (but it's very hard to convince the powers that are of that as well as the usefulness of RPN in teaching). I remember one student I tutored. The typical average student with a distaste of maths. I taught him to enter nth-roots with the '1/x' and 'y^x' keys, and I saw almost literally the lightbulb going off in his head. He surprised me in the next session by asking me about entering nth-base logarithms -- he was suddenly almost completely able to do it all by himself.

Of the currently still in production mainstream calculators, I consider the HP35s as almost ideal. Some minor problems with the display and the UI, but nothing major, though the EQN library is a little bit too easy to use for cheating (but equally as easily to work around as a teacher when giving exams).

But most parents protest at the price. It needs to be ~$/€ 20, tops.

## RPN in education

### Re: RPN in education

Sorry, RPN was indeed a typo. Sorry for any confusion. What I mean with x*pi and sqrt(n) is, that if you key in \(2 * \pi =\) in a Casio fx-whatever you'll get \(2 \pi\) on the display, not 6.28318(...). Same for \(\sqrt{2}\) or \(\sqrt{3}\) etc. And as an engineer it is sometimes useful to see, if you are close to/exactly at e. g. a multiple of \(\pi\) or \(\sqrt{n}\). (On the DM42 I use https://www.hpmuseum.org/software/qpi/42sqpi.htm for that, but I would switch it on for sure if it would be there as a default option.)

But to see these computerized "approximation" to fractions, roots and multiplexes of pi as helpful or not depends for sure on the use case and personal preference.

HP-41cx, HP-35s, DM42

### Re: RPN in education

Sounds interesting. Will it be useful to have a selectable option in C43 to display X,Y,Z&T registers as multiples of defined constants, maybe of e, π, √2, √3 & √5.

Jaco Mostert

Elec Eng, South Africa

Elec Eng, South Africa

**C43 (WP34C) on DM42 sn. 03818 & 06199**for complex math, HP42S; HP32Sii, WP34S&C, HP28C, HP35s, EL-506P, EL-W506, PB700; owned FX702P & 11C; used HP67 & HP85; iOS:**42s Byron**, Free42, WP31S/34S, HCalc.### Re: RPN in education

I thought about making a proposal for the WP43S at some point, when I had time to think about a nice usability concept for that (so it would find its way to C43 as well ). But, i think, we should find a way where the calculator recognizes automatically if the register is close or at one of or at multiples of these values and print then accordingly.

However, I would bring this optional feature up as an Gitlab-Issue to discuss at some point, but for this threads it's a little off-topic i think.

HP-41cx, HP-35s, DM42