Not to worry, we've got 6111 and 1668. Let's get to adding them!

Step 1: We'll start by adding the digits 1 & 8 in column 1 and get 9.

Step 2: We'll start by adding the digits 1 & 6 in column 2 and get 7.

Step 3: We'll start by adding the digits 1 & 6 in column 3 and get 7.

Step 4: We'll start by adding the digits 6 & 1 in column 4 and get 7.

So, 6111 + 1668 = 7779.

