OK, let's do this. We've got 52 and 335 and we're adding them all together.

Step 1: We'll start by adding the digits 2 & 5 in column 1 and get 7.

Step 2: We'll start by adding the digits 5 & 3 in column 2 and get 8.

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

So, 52 + 335 = 387.

