An important duty of the mathematics teacher is to train and to develop thinking for students. To accomplish this duty, teachers can organize creative activities for students through activities of solving problems. In particular, there is an effective way to train students to think is that teachers can organize activities of solving problems in many different ways. Based on this idea, we implement an experiment for students in grade 12 to calculate integrals in various ways. The results of the study showed that students were active to find out different solutions to the given problem.