Educating young software engineers and IT experts is a great challenge nowadays. Still new technologies are used in a practical approach and many of them come from formal methods. To help future software experts in the understanding of formal methods grounded in semantics, learning software that illustrates and visualizes important techniques seems to be very fruitful. In this paper, we present software, which handles the arithmetic and Boolean expressions, their analysis, evaluation, drawing the syntax tree and the other techniques with the expressions. This software is devoted as a teaching tool for teachers when explaining appropriate theory and for students for self-studying and making their own experiments. Furthermore, this software is an integral part of our software package for several semantic methods.