OK, let's do this. We've got 88020 and 71929, and we're subtracting the second number from the first.

Step 1: We'll start by subtracting the digit 9 and the borrow 0 from 0 in column 1 and get -9.
We add -9 to 10 and get 1 as the first digit of the result.

Step 2: We'll start by subtracting the digit 2 and the borrow 1 from 2 in column 2 and get -1.
We add -1 to 10 and get 9 as the next digit of the result.

Step 3: We'll start by subtracting the digit 9 and the borrow 1 from 0 in column 3 and get -10.
We add -10 to 10 and get 0 as the next digit of the result.

Step 4: We'll start by subtracting the digit 1 and the borrow 1 from 8 in column 4 and get 6.
6 is the next digit of our result.

Step 5: We'll start by subtracting the digit 7 and the borrow 0 from 8 in column 5 and get 1.
1 is the next digit of our result.

So, 88020 - 71929 = 16091.