Undo function:


Use this function to undo previous calculation steps.

After pressing the "Undo" button or the [Right Arrow Key] for the first time, the current content of the input area will be cleared (corresponding to the CE / Clear entry button on a common calculator). Pressing the "Undo" button or the [Right Arrow Key] for several times, undoes the previous calculation steps. The undo function is inactive during the percentage calculation [P] and the percentage change calculation [D].