The RPN calculator I normally use was missing a couple of features, so I made my own: https://nice-calculator.glitch.me/
I've written a bit about it on @aperiodical: https://aperiodical.com/2019/02/ive-made-myself-a-calculator/
@christianp @aperiodical The one I use on my phone is Free42. It simulates an HP-42S and appears to be available on both Android and iPhone (I have the Android version). Because it's a programmable calculator it probably has some of the features you were missing, but obviously it isn't going to have the nice display of the current formula.
This is amazing! I always found that RPN calculators were great for formula entry, but algebraic calculators were better for editing formulae. You've really begun to close the gap!
A Mastodon instance for maths people. The kind of people who make \(\pi z^2 \times a\) jokes.
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