For discrete mathematics, I am referring to Eric Rosen.
After reading a section I can solve most of the exercise questions in a few minutes. But some (which are marked difficult (*) or challenging (**)) take a lot more time.
How does one approach these questions? (should one be able to solve them? Then I need to find a resource better than Eric Rosen as the theory in the same isn't sufficient to solve the questions in time. Or, should one ignore them?)
Thanks in advance!