The trend of applying mathematical knowledge to solve practical problems has become a top priority goal of many mathematics educations in the world, including Vietnam. The pioneer in the concept of “realistic mathematics education” is Freudenthal (1991). He believes that “math teaching needs to be connected with situations related to everyday life, to general society to be of value to learners”. Freudenthal’s (1991) thought opened the way for the formation of a very developed theory of mathematics education in the Netherlands, called realistic mathematics education (RME), with two basic principles that mathematics must not only be linked with the real but also mathematics needs to be viewed as a human activity. By applying this theory, in this article, we have designed a teaching model based on RME, the feasibility of the model has been verified by us through two experimental teaching periods in the classroom. With positive results, we believe that the model that we have proposed according to RME’s approach can meet the goal of mathematics education in Vietnam in the current period and in the coming 21st century, and it needs to be widely studied and applied in math teaching in Vietnam.