permutation and combination. Please read the description

Question

The burger shop offers cheese, lettuce, tomato, and pickles. Assuming that you are not concerned about where the toppings are, how many different ways can you order?

Answer 1

Since the order does not made a difference:

you have 4 for the first, 3 for the second, 2 for the third, and 1 for the last

 

4 · 3 · 2 · 1 = 24