No problem, let's work through this together. We're starting with 5404 and 1303 and adding them all up.

Step 1: We'll start by adding the digits 4 & 3 in column 1 and get 7.

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

Step 3: We'll start by adding the digits 4 & 3 in column 3 and get 7.

Step 4: We'll start by adding the digits 5 & 1 in column 4 and get 6.

So, 5404 + 1303 = 6707.

