We've got two numbers: 3665 and 2001. Let's find their sum.

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 6 & 0 in column 2 and get 6.

Step 3: We'll start by adding the digits 6 & 0 in column 3 and get 6.

Step 4: We'll start by adding the digits 3 & 2 in column 4 and get 5.

So, 3665 + 2001 = 5666.

