Let's solve this addition problem. We have 3591 and 2, and we need to add them together.

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

Step 2: We'll start by adding the digits 9 & 0 in column 2 and get 9.

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 3 & 0 in column 4 and get 3.

So, 3591 + 2 = 3593.

