HP 50g with built-in HP Solve

The HP Solve application is one of the most useful feature on on the HP 50g. The solver gives you the ability to place a formula such as ROI=RETURN / INVESTMENT into the calculator using words to stand for the variables in the equation. Any known values are entered into these variables and then Solve can find the remaining unknown value without ANY programming by the user. This is a tremendous time saver. Students can use HP 50g HP Solve to solve a hypergeometric probability problem in a couple of seconds while they were working for minutes to resolve the equation by hand every time an input changed. In addition to greatly extending the functionality of the calculator, using the Solver also cuts down on careless errors.

Enter the above ROI formula in Eq: field.  Press [ENTER] key, and HP 50g generates automatically the ROI, RETURN, INVESTMENT.  Enter RETURN: and INVESTMENT: values and move cursor using the arrow key to ROI: field.  Press softkey {SOLVE} and you would get the answer.

Applicable also for HP 48gII and HP 49g+.