Solution: The sum of cubes formula is $\left(\fracn(n+1)2\right)^2$. For $n = 12$, the sum is $\left(\frac12 \cdot 132\right)^2 = (78)^2 = 6084$. Dividing by 13: $6084 \div 13 = 468$ with remainder 0, since $13 \cdot 468 = 6084$. - go-checkin.com