OK, let's do this. We've got 4663 and 4013 and we're adding them all together.

Step 1: We'll start by adding the digits 3 & 3 in column 1 and get 6.

Step 2: We'll start by adding the digits 6 & 1 in column 2 and get 7.

Step 3: We'll start by adding the digits 6 & 0 in column 3 and get 6.

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

So, 4663 + 4013 = 8676.

