I am currently using this textbook to study applied combinatorics: Applied combinatorics, 6th edition by Alan Tucker. However, I have a super hard time doing anything that deals with the addition principle, multiplication principle, the use of !, the use of power, distribution, arrangements, selection, etc...
My situation is this:When I see the question, I can't come up with any thoughts, can't understand at all. But after I looked at the solution, I felt it was not that hard.
What should I do? What can I do? I am so frustrated and so headache whenever I do combinatorics... But I have to get through this class, I don't know, I am so lost right now...
