A calculating device includes a receiver-and-transmitter and a processor. The receiver-and-transmitter is configured to communicate with a server. The processor performs processes including: transmitting (i) an increment of an independent variable per one display dot according to a variance range of the independent variable and the number of display dots on a screen, (ii) a function expression of the independent variable, and (iii) the variance range of the independent variable, to the server; receiving coordinate data of each display dot for generating a graph in a graph display range on the screen, from the server; and displaying a graph image generated at each display dot of the graph display range based on the coordinate data.