Abstract: An improved educational calculator permits sequential display of equations as transformations are made to solve the equations.First simultaneous linear equations are entered, and each time an advance key is depressed, process equations, obtained by transforming the equations step by step to reach their answers, are successively displayed on a liquid-crystal display screen. Each time a return key is depressed, the process equations are successively displayed from the answers to the equations in a reverse manner. The problem-solving method is selected through the entry of a solution key among the addition and subtraction method, the substitution method and the equivalence method, which are learned in the junior high school. The sequential display mode of the process equations can be switched between the automatic sequential display and the display on the basis of each entry of the advance key and the return key.

Abstract: The invention provides a calculator wherein it is possible to start an operation on the basis of an inputted formula and successively know the progress processes of operation until an operation result is obtained. An inputted formula edited on the basis of the data inputted from a keyboard is once displayed and the calculator is placed in the state of waiting for key entry. Then, when a Enter key is pressed down, only the operator codes selected among plural operator codes in the inputted formula in accordance with the priority order of operation are processed and a process formula as the result of the processing is displayed. Thereafter, every time the Enter key is pressed down, the operation is executed in accordance with the priority order and the process formulas obtained in the respective operations are successively displayed.