Maybe make it possible to swipe out the numberpad to add more scientifc options. To the left you could have a numberpad with Hex Key like A, B. C, D, E, F and you can switch between Dezimal, Binary, and Hex. To the right you could have the standard stuff like sin(), arc(), sqrt() etc.

Nice mockup! I want to combine buttons " ( " and " ) " to one " () ", and I like when answer is auto calculated (without pressing " = " button).
Additional functions like sin, cos, sqrt can be added at the same buttons, e.g. press " 2 " and swype up. It is made in calculator++ on android.

A table of Physics constants would be sweet!