Alright, let's solve this problem step by step. We have 8556 and 3018 and we're adding them together.

Step 1: We'll start by adding the digits 6 & 8 in column 1 and get 14.
We'll write down the last digit 4 and carry the 1 to the next column.

Step 2: We'll start by adding the digits 5 & 1 in column 2 and get 7.

Step 3: We'll start by adding the digits 5 & 0 in column 3 and get 5.

Step 4: We'll start by adding the digits 8 & 3 in column 4 and get 11.
We'll write down the last digit 1 and carry the 1 to the next column.

So, 8556 + 3018 = 11574.

