These are notes of my Discrete Mathematics lectures held for students in Communication and Electric Engineering at Sapienza, the University of Roma. Roughly, the course is composed of the following parts:&nbsp;1. Elements of Number Theory&nbsp;2. elements of modern algebra&nbsp;3. elements of combinatorics&nbsp;4. elements of graph theory<br />My objective was to illustrate several topics in dierent areas of modern mathematics into which Discrete Mathematics can be subdivided. Moreover, I wanted to give an \experimental&quot; approach to the study of the material by repeatedly inviting students, whenever possible or feasible, to use a computer and a computer algebra system to carry out experimentation. Given the great variety of possible topics it was dicult to select a single book containing everything I wanted to show and only that. I therefore consulted many dierent sources that are acknowledged in the bibliography and I recommend them for further study. Some sections written in smaller fonts can be skipped or skimmed in a rst reading as they do not properly belong to a traditional course on Discrete Mathematics, but that I felt important enough to include here with the aim of stimulating the curiosity of inquiring young minds.