Alright, let's solve this problem step by step. We have 6112 and 9553 and we're adding them together.

Step 1: We'll start by adding the digits 2 & 3 in column 1 and get 5.

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 6 & 9 in column 4 and get 15.
We'll write down the last digit 5 and carry the 1 to the next column.

So, 6112 + 9553 = 15665.

