Although the content of arithmetic progression frequently has appeared the general certificate of high school recent years, this knowledge content also has many practical applications. However, teachers who teach in many high schools, are still heavily theoretical, mainly just stopping at giving formulas and solutions and then applying them to problem solving when imparting the knowledge to the students.Training is very basic, students passively acquire knowledge "mechanically". To solve the above problem, the article presents the design of a teaching situation on the topic of addition according to the theory of mathematical operations and reports the experimental results obtained in high schools Phu Huu. (Chau Thanh town, Hau Giang province).