Method and electronic machine for teaching arithmetic computation

Claim 1

In an electronic machine for teaching arithmetic computation, display means having a plurality of display locations, manually operable numeral selecting means for selecting problem and computation numerals to be displayed at said locations, manually operable function selecting means for selecting arithmetic functions to be carried out with the selected problem numerals, electronic operatively connected with both of said selecting means and with said display means for controlling the latter to display manually selected problem and computation numerals and for automatically performing correct arithmetic computations with signals received from said function selecting means, said electronic means actuating said display means to display only the manually selected problem and computation numerals, and comparing means operatively connected with said electronic means and with said display means for comparing the automatically determined but not displayed correct computations step-by-step with the manually selected computation numerals as each of the latter numerals is selected during a sequential computation enumeration from which a result is elicited and said display means including a nonnumerical indicating means operatively connected with said comparing means to be actuated thereby for indicating whether the manually selected and displayed computation numerals are correct as each of the latter numerals appears at said display means in response to operation of said manually operable numeral selecting means by the operator so that the operator without receiving an indication of the correct numeral can replace at a given display location an incorrect numeral with another numeral until the correct numeral is displayed.