Let's get this math done. We have 7005 and 9721 and we're going to add them all together.

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

Step 2: We'll start by adding the digits 0 & 2 in column 2 and get 2.

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 7 & 9 in column 4 and get 16.
We'll write down the last digit 6 and carry the 1 to the next column.

So, 7005 + 9721 = 16726.

