In this paper, the fire control system for tanks (FCS) is presented, as a complex system, by means of which the target is detected, the necessary elements are occupied and shooting is carried out. The components of the FCS, the way in functions, and the way it is maintained are presented. The essence of FCS is presented in the form of algorithms, which includes all events, from the moment of target detection, to the firing order. The concept of direct fire is explained, as a model, which is characteristic in tank battles, with the problems and errors tha may appear. Mathematical models for solving the problem of shooting in the horizontal and vertical planes have been set up. Also, the problem of shooting from a tank, when it is under a certain lateral inclination, in relation to the horizontal plane, where the shoulder of the cannon cradle is tilted, is explained. The mathematical model in this situation, which is presented in the paper, refers to the calculation of corrected angles of direction and elevation. In addition to FCS, in tank combat, one of the main factors for the success of the mission is the training of the crew. Based on all the set mathematical models, an example of a tank battle, consisting of two tanks, is shown. Tank combat is presented in the form of an algorithm, which includes all activities from target detection, through determining the necessary elements, to shooting.