"*What is the probability of rolling six standard, six-sided dice and getting six distinct numbers?*"

Doesn't matter what the first one is: probability = 1

There are 5 possibilities for the second one: probability = 5/6

There are 4 possibilities for the third one: probability = 4/6

There are 3 possibilities for the fourth one: probability = 3/6

There are 2 possibilities for the fifth one: probability = 2/6

There is 1 possibility for the sixth one: probability = 1/6

Overall probability is obtained by multiplying all the above together (then reduce to lowest terms).