Abstract: In the apparatus of the present invention for processing data contents of totalizing memories, item signs and arithmetic signs are preset in memory terms to be processed such as weight, price and so forth. The apparatus comprises an internal memory having a matrix-like memory processing table where processing numerical expressions are set by combination of items signs and arithmetic signs at predetermined addresses of the table constituted by the totalizing memories with designated addresses and the memory processing timing in respect of such memories; and an external input means for designating a desired address in the internal memory and changing and inputting the processing numerical expression of the matrix-like table thereto. Thus the contents of the totalizing memories can be altered and set easily by the numerical expressions which are changeable by such external input means, hence facilitating alteration of the contents to be totalized at the user level.