OK, let's do this. We've got 2388 and 6339 and we're adding them all together.

Step 1: We'll start by adding the digits 8 & 9 in column 1 and get 17.
We'll write down the last digit 7 and carry the 1 to the next column.

Step 2: We'll start by adding the digits 8 & 3 in column 2 and get 12.
We'll write down the last digit 2 and carry the 1 to the next column.

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

Step 4: We'll start by adding the digits 2 & 6 in column 4 and get 8.

So, 2388 + 6339 = 8727.

