Let's stop at the table

We have glasses, spoons and three-color knives. 

      • The first proposal is to make as many different sets of drop-spoon-knife as possible. Reflect and do it systematically, what is the operation that gives us the number of different sets? 
      • The second proposal consists of making sets, but where there are no repeated colors. What is now the mathematical operation that gives us the number of sets without repeated colors?