We have numbers 7935 and 2004. 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 3 & 0 in column 2 and get 3.

Step 3: We'll start by adding the digits 9 & 0 in column 3 and get 9.

Step 4: We'll start by adding the digits 7 & 2 in column 4 and get 9.

So, 7935 + 2004 = 9939.

