Discrete Mathematics: an Open Introduction
To support my students in Discrete Mathematics, I wrote a free and open source textbook, Discrete Mathematics: an Open Introduction. The book is now in its 3rd edition and has been adopted at over 30 universities around the world.
You can download the book (completely free), view the online interactive version, or find a link to an inexpensive print copy on the book’s website.
Exploring Combinatorial Mathematics
At UNC we teach a discrete mathematics course for in-service secondary teachers pursuing a Master’s degree in mathematics with a teaching emphasis. Richard Grassl and I wrote an open textbook to use in this class, which is now available.