I love the ground-up design. However, i feel that in-place operations are missing from your rationale. Good algebraic calculators are typically able to 1/x or i

I love the ground-up design. However, i feel that in-place operations are missing from your rationale. Good algebraic calculators are typically able to 1/x or invert anything on the screen with one button without breaking the input flow, and repeat operations for the same left- or right-side operand by pressing =. This massively reduces the time spent on certain guesstimations when doing napkin math.