Not to worry, we've got 12 and 8535. Let's get to adding them!

Step 1: We'll start by adding the digits 2 & 5 in column 1 and get 7.

Step 2: We'll start by adding the digits 1 & 3 in column 2 and get 4.

Step 3: We'll start by adding the digits 0 & 5 in column 3 and get 5.

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

So, 12 + 8535 = 8547.

