Probability that an event will not occur?

To find the probability that an event will not occur, you work out the probability that it will occur, and then take this number away from 1. For example, the probability of not rolling two 6s in a row can be worked out the following way:

The probability of rolling two 6s in a row is 1/6 x 1/6 = 1/36

Thus the probability of not rolling two 6s in a row is 1 - 1/36

=35/36.