Okay, we are given 5591 and 2228. Let's add them up step by step.

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 9 & 2 in column 2 and get 11.
We'll write down the last digit 1 and carry the 1 to the next column.

Step 3: We'll start by adding the digits 5 & 2 in column 3 and get 8.

Step 4: We'll start by adding the digits 5 & 2 in column 4 and get 7.

So, 5591 + 2228 = 7819.

