Buttons are too small on the Apple Watch
I would think it would work much better if the main screen on the Apple Watch for CALC would look much like the unlock screen. That is, the 10 numeric buttons under the current input line. Then, if I could just slide the numeric buttons out and replace them with the operator buttons in a similar pattern and button sizes with the current input calculation remaining on both screens.
As you have implemented it, the buttons are too small for me to accurately tap them to perform a quick simple calculation.
Coming out in v3.4.7 – Tap the expression for backspace, tap results to clear and/or to store into the new watch history :-)