We have numbers 340 and 425. Let's start adding them together.

Step 1: We'll start by adding the digits 0 & 5 in column 1 and get 5.

Step 2: We'll start by adding the digits 4 & 2 in column 2 and get 6.

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

So, 340 + 425 = 765.

