Okay, we are tasked with adding 5304 and 2103. Let's begin!

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

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 3 & 1 in column 3 and get 4.

Step 4: We'll start by adding the digits 5 & 2 in column 4 and get 7.

So, 5304 + 2103 = 7407.

