Okay, we are tasked with adding 5512 and 1155. Let's begin!

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

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 5 & 1 in column 3 and get 6.

Step 4: We'll start by adding the digits 5 & 1 in column 4 and get 6.

So, 5512 + 1155 = 6667.

