Entack RPN is an easy-to-use, powerful calculator. It has a fully editable 100-position stack(10 viewable, with a 10-position memory. It also had an Undo button, Backspace button and clear buttons nexr to a conveniently and compactly arranged basic arithmetic functions. There is also a panel of advanced functions such as, power, log, trigonometric (Radians or Degrees mode), and other advanced functions. All values are displayed in either engineering notation or fixed decimal places (0 - 8 digits). Version 2.0 is more reliable, had more functions and better saves your settings.