Okay, we are tasked with adding 8002 and 1587. Let's begin!

Step 1: We'll start by adding the digits 2 & 7 in column 1 and get 9.

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 0 & 5 in column 3 and get 5.

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

So, 8002 + 1587 = 9589.

