Okay, we are tasked with adding 6120 and 3287. Let's begin!

Step 1: We'll start by adding the digits 0 & 7 in column 1 and get 7.

Step 2: We'll start by adding the digits 2 & 8 in column 2 and get 10.
We'll write down the last digit 0 and carry the 1 to the next column.

Step 3: We'll start by adding the digits 1 & 2 in column 3 and get 4.

Step 4: We'll start by adding the digits 6 & 3 in column 4 and get 9.

So, 6120 + 3287 = 9407.

