Peter rolls two standard six-sided dice at the same time. What is the probability that the sum of both rolls is a prime number less than $6$? 
Overseas Competition->Knowledge Point->Counting Modules->Statistics and Probability->Questions Involving Probability->Basic Concepts of Probability
There are $7$ out of $36$ outcomes which are prime numbers under $6$: $1+1$, $1+2$, $1+4$, $2+1$, $2+3$, $3+2$, $4+1$. 