A five letter code is to be made by choosing 5 letters from the first 7 letters of our alphabet (a, b, c, d, e, f, g).  If repeats are allowed (the same letter may be used used more than once), how many possible codes (outcomes) can be made

A teacher will randomly award three students with extra credit. How many possible ways can the teacher pick these three students from a class of 20 students?

If you pick 4 cards without replacement from a standard deck of 52 cards, how many different combinations are possible?

There are 10 trivia teams (Teams A through J), each with 5 members. 16 areselected for an all-star team. How many ways are there to select an all-star team which includes all members from A, all members from B, all members from C, or all members from D?