Okay, we are given 3876 and 20. Let's add them up step by step.

Step 1: We'll start by adding the digits 6 & 0 in column 1 and get 6.

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

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

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

So, 3876 + 20 = 3896.

