Not to worry, we've got 8523 and 1404. Let's get to adding them!

Step 1: We'll start by adding the digits 3 & 4 in column 1 and get 7.

Step 2: We'll start by adding the digits 2 & 0 in column 2 and get 2.

Step 3: We'll start by adding the digits 5 & 4 in column 3 and get 9.

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

So, 8523 + 1404 = 9927.

