Okay, we are tasked with adding 5103 and 3805. Let's begin!

Step 1: We'll start by adding the digits 3 & 5 in column 1 and get 8.

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

Step 3: We'll start by adding the digits 1 & 8 in column 3 and get 9.

Step 4: We'll start by adding the digits 5 & 3 in column 4 and get 8.

So, 5103 + 3805 = 8908.

