Let's get this math done. We have 8515 and 1120 and we're going to add them all together.

Step 1: We'll start by adding the digits 5 & 0 in column 1 and get 5.

Step 2: We'll start by adding the digits 1 & 2 in column 2 and get 3.

Step 3: We'll start by adding the digits 5 & 1 in column 3 and get 6.

Step 4: We'll start by adding the digits 8 & 1 in column 4 and get 9.

So, 8515 + 1120 = 9635.

