A fair $6-$sided die is rolled twice. What is the probability that the sum of the two rolls\textquotesingle{} outcomes is a perfect square? 
Overseas Competition->Knowledge Point->Number Theory Modules->Perfect Square Numbers->Basic Applications of Square Numbers
There are $7$ out of $36$ outcomes are perfect squares: $1+3$, $2+2$, $3+1$, $3+6$, $4+5$, $5+4$, $6+3$. 