Alright, let's solve this problem step by step. We have 3635 and 9480 and we're adding them together.

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

Step 2: We'll start by adding the digits 3 & 8 in column 2 and get 11.
We'll write down the last digit 1 and carry the 1 to the next column.

Step 3: We'll start by adding the digits 6 & 4 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 3 & 9 in column 4 and get 13.
We'll write down the last digit 3 and carry the 1 to the next column.

So, 3635 + 9480 = 13115.

