Okay, we are given 5816 and 2003. Let's add them up step by step.

Step 1: We'll start by adding the digits 6 & 3 in column 1 and get 9.

Step 2: We'll start by adding the digits 1 & 0 in column 2 and get 1.

Step 3: We'll start by adding the digits 8 & 0 in column 3 and get 8.

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

So, 5816 + 2003 = 7819.

