Okay, let's tackle this math problem. We're starting with 3320 and subtracting 3247.

Step 1: We'll start by subtracting the digit 7 and the borrow 0 from 0 in column 1 and get -7.
We add -7 to 10 and get 3 as the first digit of the result.

Step 2: We'll start by subtracting the digit 4 and the borrow 1 from 2 in column 2 and get -3.
We add -3 to 10 and get 7 as the next digit of the result.

Step 3: We'll start by subtracting the digit 2 and the borrow 1 from 3 in column 3 and get 0.
0 is the next digit of our result.

Step 4: We'll start by subtracting the digit 3 and the borrow 0 from 3 in column 4 and get 0.
0 is the next digit of our result.

So, 3320 - 3247 = 73.