Okay, we are tasked with adding 3240 and 6135. Let's begin!

Step 1: We'll start by adding the digits 0 & 5 in column 1 and get 5.

Step 2: We'll start by adding the digits 4 & 3 in column 2 and get 7.

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

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

So, 3240 + 6135 = 9375.

