Not to worry, we've got 1284 and 8531. Let's get to adding them!

Step 1: We'll start by adding the digits 4 & 1 in column 1 and get 5.

Step 2: We'll start by adding the digits 8 & 3 in column 2 and get 11.
We'll write down the last digit 1 and carry the 1 to the next column.

Step 3: We'll start by adding the digits 2 & 5 in column 3 and get 8.

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

So, 1284 + 8531 = 9815.

