Okay, we are given 5520 and 1335. Let's add them up step by step.

Step 1: We'll start by adding the digits 0 & 5 in column 1 and get 5.

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

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

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

So, 5520 + 1335 = 6855.

