Question 7
In the following alphametic, all different letters stand for different digits. Find the two-digit sum $\overline{PI}$.
$\overline{IS}+\overline{IS}+\overline{IS}+\overline{IS}=\overline{PI}$.

$\overline{IS}+\overline{IS}+\overline{IS}+\overline{IS}=\overline{PI}$.
