The space of events is the set of all pairs of integer numbers (i,j), where i and j are between 1 and 6, inclusively. So, the set of events has 6*6 = 36 elements, all with the same probability of. Of them, the favorable are those, where i and j are different: i =/= j. The number of those with i = j is 6. So, the favorable set consists of 36 - 6 = 30 elements. Therefore, the probability under the question is P = = .