Not to worry, we've got 2553 and 8591. Let's get to adding them!

Step 1: We'll start by adding the digits 3 & 1 in column 1 and get 4.

Step 2: We'll start by adding the digits 5 & 9 in column 2 and get 14.
We'll write down the last digit 4 and carry the 1 to the next column.

Step 3: We'll start by adding the digits 5 & 5 in column 3 and get 11.
We'll write down the last digit 1 and carry the 1 to the next column.

Step 4: We'll start by adding the digits 2 & 8 in column 4 and get 11.
We'll write down the last digit 1 and carry the 1 to the next column.

So, 2553 + 8591 = 11144.

