Each of five, standard, six-sided dice is rolled once. What is the probability that there is at least one pair among all five rolls? (In other words, what is the probability that at least two rolls are equal?)

6/6 x 5/6 x 4/6 x 3/6 x 2/6==6! / 6^5==5 / 54 - this is the probability that they are all DIFFERENT.

1 - 5/54 ==49 / 54 - probability of getting at least one matching pair.