the specification discloses a hand - held calculator of the type used by teachers in averaging grades . the calculator permits intermixed entry of letter grades and numeric grades in an averaging sequence . a weight table may be stored in the calculator for automatic nonlinear weighting of inputted grades in the averaging process . an excused absence key permits a data entry that will not affect the average of the other inputted grades . the calculator permits display in any one of a variety of modes , such as letter grade , percent , and total points .