Okay, we are tasked with adding 3128 and 3671. Let's begin!

Step 1: We'll start by adding the digits 8 & 1 in column 1 and get 9.

Step 2: We'll start by adding the digits 2 & 7 in column 2 and get 9.

Step 3: We'll start by adding the digits 1 & 6 in column 3 and get 7.

Step 4: We'll start by adding the digits 3 & 3 in column 4 and get 6.

So, 3128 + 3671 = 6799.

