The proposed mathematical "simulator" corresponds to the State Standard of Primary Education, Model Educational Programmes and textbooks in mathematics for the 4th grade. The simulator card includes 10-20 expressions and one task. In each lesson, students solve the expressions for 3 minutes. The teacher records the time and assesses the correctness of the tasks. The student who completes the calculation faster solves the problem and colours the picture. This guide can also be used for work at home.