Not to worry, we've got 3264 and 4135. Let's get to adding them!

Step 1: We'll start by adding the digits 4 & 5 in column 1 and get 9.

Step 2: We'll start by adding the digits 6 & 3 in column 2 and get 9.

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 & 4 in column 4 and get 7.

So, 3264 + 4135 = 7399.

