OK, let's do this. We've got 7221 and 1464 and we're adding them all together.

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 & 6 in column 2 and get 8.

Step 3: We'll start by adding the digits 2 & 4 in column 3 and get 6.

Step 4: We'll start by adding the digits 7 & 1 in column 4 and get 8.

So, 7221 + 1464 = 8685.

