I-Multiplication Rules

1. How many different slats can be made. If the splint is composed of 4 letters and 3 digits.

2. How many special shuttle crews can be formed if: for pilot position, co-pilot and flight engineer there are (8) eight candidates, for two scientists one for solar experiment and one for stellar experiment there are (6) candidates and for two Civilians there are (9) candidates.

II-permutations and combinations

1. In a raffle where there are 10 possible numbers in each ball, if three pellets are extracted. How many ways is it possible to combine extracted numbers?

2. Ten people reach a row at the same time. How many ways can they be formed?

3. In a Olympiad there are 10 swimmers in a race, how many ways can arrive the first three places?

4. How many committees of three teachers can be made if there are 6 teachers to choose from?