OK, let's do this. We've got 8517 and 311 and we're adding them all together.

Step 1: We'll start by adding the digits 7 & 1 in column 1 and get 8.

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

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

Step 4: We'll start by adding the digits 8 & 0 in column 4 and get 8.

So, 8517 + 311 = 8828.

