OK, let's do this. We've got 8820 and 5997 and we're adding them all together.

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 & 9 in column 2 and get 11.
We'll write down the last digit 1 and carry the 1 to the next column.

Step 3: We'll start by adding the digits 8 & 9 in column 3 and get 18.
We'll write down the last digit 8 and carry the 1 to the next column.

Step 4: We'll start by adding the digits 8 & 5 in column 4 and get 14.
We'll write down the last digit 4 and carry the 1 to the next column.

So, 8820 + 5997 = 14817.

