OK, let's do this. We've got 9015 and 700 and we're adding 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 & 0 in column 2 and get 1.

Step 3: We'll start by adding the digits 0 & 7 in column 3 and get 7.

Step 4: We'll start by adding the digits 9 & 0 in column 4 and get 9.

So, 9015 + 700 = 9715.

