How do I prove the sum/product rule in combinatorics? I think I should use induction but how do I start?
What should be the base case and the ... erm induction step?
Sum rule: suppose that an operation can be broken down into two tasks $A$ and $B$ if there are $N_a$ ways to do task $A$ and $N_b$ ways to do task $B$, the number of ways to do the operation is $N_a + N_b$
for product rule its the same only that its $N_aN_b$