No problem, let's work through this together. We're starting with 2111 and 6555 and adding them all up.

Step 1: We'll start by adding the digits 1 & 5 in column 1 and get 6.

Step 2: We'll start by adding the digits 1 & 5 in column 2 and get 6.

Step 3: We'll start by adding the digits 1 & 5 in column 3 and get 6.

Step 4: We'll start by adding the digits 2 & 6 in column 4 and get 8.

So, 2111 + 6555 = 8666.

