OK, let's do this. We've got 2160 and 3221 and we're adding them all together.

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

Step 2: We'll start by adding the digits 6 & 2 in column 2 and get 8.

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

Step 4: We'll start by adding the digits 2 & 3 in column 4 and get 5.

So, 2160 + 3221 = 5381.

