Does a pretty good job as a RPN calculator. I only tried the basic four function. Tried to string calculations together: 166 / 60 * 2 * 6 but wasn’t able to. I would get the first calculation, but wasn’t able to push the result to the stack. I tried to press [Enter], but there was no response Tried to use a function key (+ or / or *) and that wouldn’t work either. Also didn’t like that if force my iPad to portrait orientation. Found no settings to change this. Okay, so what do you want for free? Please sir (or madam) a little more functionality please.I deleted my copy, but will keeping my eye out for updates. The author needs to add a way to push and rotate the stack. There should be a memory button to store results regardless of stack, and lastly a way to change the orientation to landscape based on the accelerometer. In landscape, the buttons should go on one side, and the stack and answer should go on the other.