We have numbers 3020 and 803. Let's start adding them together.

Step 1: We'll start by adding the digits 0 & 3 in column 1 and get 3.

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

Step 3: We'll start by adding the digits 0 & 8 in column 3 and get 8.

Step 4: We'll start by adding the digits 3 & 0 in column 4 and get 3.

So, 3020 + 803 = 3823.

