Okay, we are given 4021 and 4745. Let's add them up step by step.

Step 1: We'll start by adding the digits 1 & 5 in column 1 and get 6.

Step 2: We'll start by adding the digits 2 & 4 in column 2 and get 6.

Step 3: We'll start by adding the digits 0 & 7 in column 3 and get 7.

Step 4: We'll start by adding the digits 4 & 4 in column 4 and get 8.

So, 4021 + 4745 = 8766.

