where 
2. Prove a recurrence relation formula using induction. For example, exercises 2, 3, 4, 6, 7, 8 in 9.2
3. Prove some equivalences for combinations using the factorial formula. For example 8.1 # 26, 29, 30
4. Use the binomial theorem to expand a binomial. For example 8.1 # 5-18
5. Use the pigeonhole principle to determine a max1mum or minimum amount for a set (sec 8.2 # 1-8)
6. Use the combinations, permutations, multiplication and division to determine numbers of possible arrangements or groupings (see sections 8.2 and 8.3)
7. Find numbers of possible arrangements or selections where repetition is possible (section 8.4)
8. Use sample spaces with equally likely possibilities to determine probabilities (section 8.5)
9. Use Inclusion-Exclusion to determine total amounts from information about the sets that make up the total.