No problem, let's work through this together. We're starting with 7335 and 1231 and adding them all up.

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

Step 2: We'll start by adding the digits 3 & 3 in column 2 and get 6.

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

Step 4: We'll start by adding the digits 7 & 1 in column 4 and get 8.

So, 7335 + 1231 = 8566.

