“I’m Not Dead Yet!” Reverse Polish Notation Calculators You Can Still Buy

“RPN isn’t exactly the way people calculate with pencil and paper, and it certainly wasn’t derived from the slide rule, but there is a similarity in the way you work. With a slide rule, you generally establish some value, operate on it, and continue from the result. When doing a long-hand calculation, you often calculate a subexpression, write down the answer, and use that answer in the next step. You will probably start with the inner parenthesis and work outward, just like someone with an RPN calculator does. RPN formalises that process with a stack.” I still have my HP41CV, and it still works well 40 years on. RPN is actually a highly effective way of doing complex calculations. Once it is understood, it is quite intuitive. My HP41CV was RPN-only, so I got very used to using it. It is good to see there are still options available to buy, and I did not know about the Linux AppImage for HP Prime Virtual Calculator. Neither had I seen the CalcTastic Android app — must say it works…