Abstract: The memory (80) is intended to be read or modified by an electronic logical system of a pocket calculator. It comprises a plurality of bistable electromechanical flip-flop circuits (82). Each flip-flop circuit (82) comprises an input for setting at 1 (S) and an input for setting a zero (R) and an output (78). The inputs are connected individually to a multiplexor (702) controlled by a control circuit (701). The control circuit (701) is connected in two directions with a central processor via a bus (51). The control circuit (701) manages readings and writings to the memory (80).The memory is intended to memorize data which have to be retained in the calculator in a reliable and convenient way, even if the supply is cut off. The calculator is, for example, intended to make calculations concerning the application of the Ogino method, the data to be memorized being the durations of previous cycles and the date of the last period.