OK, let's do this. We've got 9989 and 7482 and we're adding them all together.

Step 1: We'll start by adding the digits 9 & 2 in column 1 and get 11.
We'll write down the last digit 1 and carry the 1 to the next column.

Step 2: We'll start by adding the digits 8 & 8 in column 2 and get 17.
We'll write down the last digit 7 and carry the 1 to the next column.

Step 3: We'll start by adding the digits 9 & 4 in column 3 and get 14.
We'll write down the last digit 4 and carry the 1 to the next column.

Step 4: We'll start by adding the digits 9 & 7 in column 4 and get 17.
We'll write down the last digit 7 and carry the 1 to the next column.

So, 9989 + 7482 = 17471.

