Alright, let's solve this problem step by step. We have 396 and 3601 and we're adding them together.

Step 1: We'll start by adding the digits 6 & 1 in column 1 and get 7.

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 3 & 6 in column 3 and get 9.

Step 4: We'll start by adding the digits 0 & 3 in column 4 and get 3.

So, 396 + 3601 = 3997.

