Not to worry, we've got 15 and 6960. Let's get to adding them!

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 & 6 in column 2 and get 7.

Step 3: We'll start by adding the digits 0 & 9 in column 3 and get 9.

Step 4: We'll start by adding the digits 0 & 6 in column 4 and get 6.

So, 15 + 6960 = 6975.

