It well known that scientists and engineers communicate with each other, with not just the oral and written language, but with equations and diagrams.  It is no wonder that STEM related subject teachers and students rely heavily on equations and diagrams when they teach and learn their subject, respectively.  However, due to the multitude of problems encountered when teaching large STEM related classes (e.g., low student engagement, limited options for checking student understanding and feedback (in real-time), diversity of students), there is a stark absence of students communicating and engaging with their instructor (or with other students), in class, through the writing of equations and the drawing of diagrams.  In this presentation, we will describe two new e-tools that will help the teacher and student actively teach and learn in a large STEM related subjects through writing equations and drawing diagrams called YoTeach! and Badaboom!  YoTeach! is a web-based online backchannel with drawing functionalities (yoteach.hk) and Badaboom! is a Kahoot! like web-based game learning platform with math/symbol/writing recognition functionality (badaboom.hk).  We will show how to use YoTeach! to enhance the simple "question and answer" active teaching strategy; and how to use Badaboom! to increase "problem based collaborative learning" active pedagogy in a large classroom.