We have numbers 1004 and 2301. Let's start adding them together.

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

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

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

Step 4: We'll start by adding the digits 1 & 2 in column 4 and get 3.

So, 1004 + 2301 = 3305.

