Let's solve this addition problem. We have 304 and 540, and we need to add them together.

Step 1: We'll start by adding the digits 4 & 0 in column 1 and get 4.

Step 2: We'll start by adding the digits 0 & 4 in column 2 and get 4.

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

So, 304 + 540 = 844.

