We have numbers 1205 and 1434. Let's start adding them together.

Step 1: We'll start by adding the digits 5 & 4 in column 1 and get 9.

Step 2: We'll start by adding the digits 0 & 3 in column 2 and get 3.

Step 3: We'll start by adding the digits 2 & 4 in column 3 and get 6.

Step 4: We'll start by adding the digits 1 & 1 in column 4 and get 2.

So, 1205 + 1434 = 2639.

