Question 3
Two digits are to be added to the number $2021$, one on the left and one on the right, to form a six-digit number $N$. For example, we obtain the number $820219$ if we add $8$ to the left and $9$ to the right. If we know that $N$ is a multiple of $28$, what is the smallest possible value of the sum of the digits of $N$?