Alright, let's solve this problem step by step. We have 91921 and 75202, and we're subtracting the second number from the first.

Step 1: We'll start by subtracting the digit 2 and the borrow 0 from 1 in column 1 and get -1.
We add -1 to 10 and get 9 as the first digit of the result.

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

Step 3: We'll start by subtracting the digit 2 and the borrow 0 from 9 in column 3 and get 7.
7 is the next digit of our result.

Step 4: We'll start by subtracting the digit 5 and the borrow 0 from 1 in column 4 and get -4.
We add -4 to 10 and get 6 as the next digit of the result.

Step 5: We'll start by subtracting the digit 7 and the borrow 1 from 9 in column 5 and get 1.
1 is the next digit of our result.

So, 91921 - 75202 = 16719.