In recent years, Ministry of Education has required and encouraged the use of information technology in learning and teaching at secondary high schools. The question is being raised that how to use information technology efficiently because there are some comments on the abuses of information technologies, particularly in teaching and learning mathematics. A classification of levels of use of information technology in the article may be useful for orientation to implement and analyze teaching situations. In addition, the article also introduces calculators as a supportive tool to design teaching situation in the trend of using information technology.