I've checked out a number of calculator apps, either free or max €1 ones, and found this one pretty good (for simple math only, dont need scientific part) — except for one fatal flaw, which almost defies its own purpose: the tape of past calcs appears to the RIGHT of the calculator, which –me being right-handed– is partly covered by my hand/fingers most of the time when keying in numbers. For anyone left-handed this probably works fine. (So I guess its developer is a leftie as well :). For all others, the tape should of course have been placed to the LEFT. Better stll, it should have been a prefs setting. I truly cannot understand how any developer can fail so utterly in grasping such basic-basic-basic UI considerations.