Since this course is not directly examined (its purpose is mainly to (re-) introduce discrete mathematics needed for the `Data Structures and Algorithms Course') there is no obvious source of questions. For additional problems I would suggest that you turn to the Teaching and Learning Guides issued by the (two different) Discrete Mathematics courses given as part of the Diploma/Part 2 General and as part of the Computer Science Tripos (Part 1A).
The general areas covered in the four lectures are
If you want more reading on this sort of material, I recommend ``Concrete Mathematics'' by Knuth, Graham and Patashnik. It obviously contains much more that can fit in my four lectures, but a great deal of what it contains could find direct use somewhere in a computer science course. The Schaum-series book `Discrete Mathematics' contains some 700 worked problems and is in general quite useful.