Alright, let's solve this problem step by step. We have 8503 and 84 and we're adding them together.

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 0 & 8 in column 2 and get 8.

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

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

So, 8503 + 84 = 8587.

