“Why is the size of Calculator each buttons same? “
“How order is the priority of Calculator button? “
“What type Calculator is designed ,According to this priority? “

From those point,I redesign Calculator.

Calculator is for Calculation.Not for inputting number.
Consequently, the most important button is NOT number buttons.
The most important button is 4 arithmetical operation buttons.
I design those 4 arithmetical operation button is bigger than 10 number buttons.

I put those 4 buttons around number buttons(relative position).
And if you incline your iPhone to the direction of top and bottom right and left
, you can input 4 arithmetical operation.

・Future function additional plan
Equal sign input by the gesture