There are many clear advantages of using Classroom Response System (CRS) in class. When it is used effectively, CRS will promote active learning, and students will be more engaged during the lecture. However, it takes huge courage for a lecturer or module coordinator to take the first step to implement CRS in their classroom teaching. Other than having to manage the system while delivering the lecture at the same time, there are many logistical issues involved, such as the issuing and collecting the clickers. In this talk, I will share with the audience my experience of using and managing CRS in a math module of more than 400 students.BioAssociate Professor Victor Tan received his B.Sc. (Hons) degree from the National University of Singapore in 1987 and his Ph.D. degree from the University of California, Los Angeles, in 1996. He is currently the Vice-Chair of the NUS Teaching Academy. Prof. Tan was a regular winner of NUS Teaching Excellence Awards over the years. In 2007, he won the University's Outstanding Educator Award. Prof. Tan's research interests are on Algebra and Number Theory. He has also keen interest in using IT in Mathematical teaching. He uses webcasts, Breeze, Classroom Response System, virtual tutorial class as well as various IVLE tools to supplement the classroom teaching. He has also developed a web-based component called "Virtual lab" for one of his modules, which allows students to use web tools anytime anywhere to explore and visualise concepts learnt in class.