Okay, we are tasked with adding 3408 and 1040. Let's begin!

Step 1: We'll start by adding the digits 8 & 0 in column 1 and get 8.

Step 2: We'll start by adding the digits 0 & 4 in column 2 and get 4.

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

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

So, 3408 + 1040 = 4448.

