Two standard 6-sided dice are tossed. What is the probability that the sum of the numbers shown on the dice is a prime number? Express your answer as a common fraction.
The possible primes are ;
2, 3, 5, 7, 11
Probability of a 2 = 1/36
Probability of a 3 = 2/36
Probability of a 5 = 4/36
Probability of a 7 = 6/36
Probability of an 11 = 2/36
The sum of these probabilities = [1 + 2 + 4 + 6 + 2] / 36 = 15/36 = 5/12
+4620 
