OK, let's do this. We've got 91701 and 49580, and we're subtracting the second number from the first.

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

Step 2: We'll start by subtracting the digit 8 and the borrow 0 from 0 in column 2 and get -8.
We add -8 to 10 and get 2 as the next digit of the result.

Step 3: We'll start by subtracting the digit 5 and the borrow 1 from 7 in column 3 and get 1.
1 is the next digit of our result.

Step 4: We'll start by subtracting the digit 9 and the borrow 0 from 1 in column 4 and get -8.
We add -8 to 10 and get 2 as the next digit of the result.

Step 5: We'll start by subtracting the digit 4 and the borrow 1 from 9 in column 5 and get 4.
4 is the next digit of our result.

So, 91701 - 49580 = 42121.