Hi! Please help me understand these kind of questions. I have no idea how to even start with them.

Solve the problem.

1) In a Power Ball lottery, 5 numbers between 1 and 12 inclusive are drawn. These are the winning numbers. How many different selections are possible? Assume that the order in which the numbers are drawn is not important.

Solve the problem.

2) If the police have 9 suspects, how many different ways can they select 5 for a lineup?

Solve the problem.

3) License plates are made using 2 letters followed by 2 digits. How many plates can be made if repetition of letters and digits is allowed?

Evaluate the expression.

4) (9 C 4)/ (9 C 3)

Evaluate the expression.

5) 10 P 5

Evaluate the expression.

6) 9! / (7! 2!)