Got it! So, we have 91371 and 17645, and we'll subtract the latter from the former.

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

Step 2: We'll start by subtracting the digit 4 and the borrow 1 from 7 in column 2 and get 2.
2 is the next digit of our result.

Step 3: We'll start by subtracting the digit 6 and the borrow 0 from 3 in column 3 and get -3.
We add -3 to 10 and get 7 as the next digit of the result.

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

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

So, 91371 - 17645 = 73726.