Is RPN still relevant?

[carey]

RPN is intuitive in the sense that it mimics how calculations are done by hand where we start with numbers and then apply operations. However calculations aren't done by hand anymore so there's no need to mimic hand calculations and RPN's intuitiveness with numeric operations is offset by RPN's torturousness when working with equations without numbers. Math is idiomatic -- we visually recognize equation patterns (from the area of a circle \( \pi R^2 \) to a quadratic equation \( ax^2 + bx + c = 0 \) to a differential equation \( \frac{dN}{dt} = -kN \)). By inputting equations in RPN, our inherent equation pattern recognition skills become useless (imagine writing words in a sentence backwards).

HP wisely recognized this by adding equation mode in the RPN HP-32sii and the tick (') in the RPL HP28 and later RPL calculators so equations could be created algebraically. (Just to be clear, this is separate from adding algebraic mode to the HP49g and subsequent RPL models which was done for marketing). Equation mode in RPN calculators and the tick (') in RPL calculators was a necessary admission that RPN is backwards (literally!) for creating equations without numbers. I suspect that a good portion of the HP-32sii's popularity was due to its algebraic equation mode. It should be obvious to everyone why RPN is not taught in high school algebra classes and beyond, and would do students no favor if taught in earlier grades.

None of this detracts from RPN being fun, has nice workflow with chained calculations (though no longer unique since the Ans key and Ans() commands) and probably helps keeps a mind sharp into old age by engaging it to perform tasks that modern calculators can now perform on their own.