We have numbers 5604 and 4201. 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 6 & 2 in column 3 and get 8.

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

So, 5604 + 4201 = 9805.

