Interesting article but that feels like wasted effort for what is probably the most bare-bones calculator app out there. The Android calc app has the 4 operations, sin cos tan ^ ln log √ ! And that's it. I think most people serious about calculator usage either have a physical one or use another more featureful app and the others don't need such precision.
It's not wasted effort at all, as this app comes installed by default for over a billion users. Only a tiny fraction will ever install another calculator app, so the default one better work entirely correctly. When you have that many users it's hard to waste effort on making the product better.
