Okay, we are given 346 and 8503. 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 4 & 0 in column 2 and get 4.

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

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

So, 346 + 8503 = 8849.

