Hello! I have taught Discrete Math to the students of Computer Engineering. Discrete Math has been one of my favorite topics right from my college days. I have done assignments on this topic as a freelancer also. I will definitely help you in the topics you mention in Discrete Math. Functions (onetoone and onto), mathematical induction, counting(counting functions), relations, closures of relations(transitive closure), partial ordering and bounds are even the parts of foundations of Mathematics and hence, are very important. SO, I am looking forward to a hearing from you. Thank you!