Let's solve this addition problem. We have 434 and 120, 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 3 & 2 in column 2 and get 5.

Step 3: We'll start by adding the digits 4 & 1 in column 3 and get 5.

So, 434 + 120 = 554.

