Okay, we are given 2072 and 3801. Let's add them up step by step.

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

Step 2: We'll start by adding the digits 7 & 0 in column 2 and get 7.

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 2 & 3 in column 4 and get 5.

So, 2072 + 3801 = 5873.

