You and 4 friends go to a concert. in how many different ways can you sit in the assigned seats

So,

This is permutations.

To find all of the possible choices, you will have the number of seats with the mathematical exclamation mark after that number.

4 + you = 5 people

5! = 120

You and your 4 friends can sit in your seats 120 different ways.

Don't waste your time trying to find all 120 of them though.