It's not difficult to talk about the basics. The concepts are very important to remember and a little abstract to learn. It's a bit boring to have the patience to recommend books. As far as the sixth edition of Discrete Mathematics and Its Applications that I am using now is concerned, I feel that I can describe it in detail, which is very helpful to understand computer programming from the point of view of the connection with computers. At least I don't understand some things I used to program, but I understand a little after reading the contents in this book.