How many ways can 6 cars line up
is it 6 X 6
is it 6 squared?
no, think of 6 parking spots in a row
the first spot can be filled by 6 different cars, for each of those, the second spot can be filled in 5 ways, ....
no. of ways = 6x5x4x3x2x1 = 6! = 720