Here we go! We're going to add 5421 and 3330 together.

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

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 4 & 3 in column 3 and get 7.

Step 4: We'll start by adding the digits 5 & 3 in column 4 and get 8.

So, 5421 + 3330 = 8751.

