Every day the teacher has her class of ten students line up for lunch. How many different ways can the students line up?

The first student can be any of the 10.

The second student in line can be any of the remaining 9.

The third student in line can be any of the remaining 8.

...

There are 10*9*8 * ... * 3*2*1 = 10! ways for the students to line up.

10! = 3,628,800

The students can line up 3,628,800 different ways.