I’ve been an HP user since 1983 but my last calculator is this Free42 calculator. It’s fantastic and so much quicker than any of the physical calculators for complex programs.

To avoid any confusion, you could use the × or * symbol for multiplication, instead of a centre dot. Another thing: the 42S operates in the complex field by default. You can take square roots, roots, logs, trigonometric func, hyp etc. if complex numbers, which most other physical calculators cannot.

Got an SwissMicro DM42 for my CNC-course and had no clue how to use it. Thanks to this video I can add numbers together xD

Love 42 app, was an Army Engineer Surveyor in the 90's and picked it from their, used it for surveying ever since, easy to program, all the functions you need, and these days have it on all my computers and smart phones ready on hand. Many of you say the instrument or gnss cpu does it all but it is piece of mind to be able to check or change things while you are there. Special thanks to Thomas Okken and the free apps he has, well done mate.

MathWithoutBorders, I have used RPN calculators for a long time (I bought my first RPN calculator in 1983, an HP-11C) and for very complex calculations, but never once ran out of stack space as you suggest you could. Providing you always work from inside the parentheses outwards and make use of x and y swapping and stack rolling, you find that 4 registers (and perhaps last x, although I use that rarely) is all you ever need! I also find that having a bigger stack doesn't necessarily make things easier. Granted you can be a bit more careless with your calculations, but this in turn increases the risk of making mistakes. Like so many things in live, RPN needs a bit of practice but as you say yourself, once you learn RPN you don't really want to go back!

I love my DM42 which uses Free42. I love the fact that it has 34 digit precision. And plus the battery life on it is great. So you don't have to worry about programming a complex program and having your cell phone battery die. Plus the fact you can save the programs from the DM42 to the Free42 Applications.

Ah... HP42s brings me back to my university and graduate days, now a long time ago!

I share the enthusiasm of the previous posters for the Free42 (HP42s simulator). It is a beautiful little program. I have it on my Linux Mint 19.3 laptop and on my Samsung a21s mobile. I love it. And long live RPN. Free42 is a coding tour de force by Thomas Sokken, many thanks, mate.

I am using it for several months now on Mac, Windows, Linux and iPhone and I love it.

I loved my HP 42S

This is pure gold. Thanks a lot, sir!

Just to be more accurate, Free42 is not an emulator, it is a simulator. An emulator will emulate the hardware of the original platform and run the original device's ROM. Emu42, for example, does this. Free42 does not. It is a simulator that behaves like the original in every way but by using all original code by Thomas Okken. Not a single line of HP code is in Free42.

There's a great line in the movie "Down Periscope", where the engineer shouts "DBF!" which means "Diesel boats forever!" I was thinking "RPNF!" It's too bad HP dropped all of there great calculators (the HP42, the 48g, etc.). I know, you're thinking "OK, Boomer!" Did I mention I love slide rules too?

You might want to take a look at Plus42 which is Free42 on steroids from the same programmer. It's equivalent to the DM42.

Great tutorial on RPN, nice and clear, thanks!

The skin you are using has a poor contrast in the display. Instead you might want to use Georgs-HP2, which has a lighter background and darker digits. -- For your computer, it has also the keyboard key shortcuts visible. (Regards, the Georg )

I appreciate how good this calculator is, would you be able to find any angle using like 3π/4 ? Couldn't find a way to get correct answer.

I'd love to see a true pocket LISP machine -- I mean true LISP (or Scheme), not just RPL like on the HP-48. The DM42 might be repurposed for that since you can flash your own firmware on it. Sounds like a lot of work though.

I'm getting 0.0266 @14:39 on both my calculators. Is there something I'm missing?

Whare can I get the calc98?

I love mt HP35s

"I've cleared out the calculator" How ? Mine looks like a dog's dinner how to reset it?

Disappointing. I was hoping this video would not be so focussed upon the basics of RPN, and be an evaluation of the calculator, using some of the far more advanced features it is capable of. And why not even touch on the option to choose an unlimited stack instead of just TZXY? And why not mention that it can save any number of 'State' files for instant reversion to how it was set up before? - And there was no mention whatsoever that this calculator's strongest point is that it's fully programmable!