Okay, we are given 3021 and 3334. Let's add them up step by step.

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

Step 2: We'll start by adding the digits 2 & 3 in column 2 and get 5.

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 3 & 3 in column 4 and get 6.

So, 3021 + 3334 = 6355.

