Question 81
Positive integers $A$ and $B$ have the following decimal forms: $A = \overline{abcabc}$ and $B = \overline{d00d}$, where $a, b, c, d$ are decimal digits, $a \neq 0, d \neq 0$. Find all possible values of $a, b, c, d$ such that $A+B$ is a full square.