Generic equation solver interface for solving mathematicgeneric equation solver interface for solving mathematical equations al equations

A user-to-calculating device interface for the solution of mathematical equations is set out in accordance with the preferred embodiment of the present invention. The interface allows for the simple construction of equations which may be utilized or stored. Once an equation has been constructed, it may be solved. The preferred embodiment shows a device wherein equations may be solved utilizing an interface which utilizes a minimum number of key strokes. The user interface comprises a top-row-key interface, in which each menu key within a plurality of menu key are used to both store and to calculate a variable. It two labeled menu keys are pressed in succession, the machine calculates a result for the second. Otherwise, pressing a labeled menu key performs an assignment («=») operation and then stores a number and displays the number in a display line as a variable represented by the menu key pressed. Pressing an unlabeled menu key does nothing.