Remember Clear Task Manager for the iPhone? It was that simple task manager that had a very unique user interface that is definitely the way of the future. No tapping, no buttons (except typing ToDo words), no checkboxes, it was all about simple one hand operation sweeping up/down and back and forth.
Now, aeliox has introduced the same experience in a iPhone calculator, Rechner. Sweep your finger to the right to add, to the left to subtract and up to equal. There still needs to be a keyboard to typing the numbers in. Actually, to multiply, divide, and percents require a down swipe to uncover the buttons for those. Two finger swipe is like hitting a clear button.