OK, let's do this. We've got 83509 and 5539, 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 9 in column 1 and get 0.
0 is the first digit of our result.

Step 2: We'll start by subtracting the digit 3 and the borrow 0 from 0 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 5 and the borrow 1 from 5 in column 3 and get -1.
We add -1 to 10 and get 9 as the next digit of the result.

Step 4: We'll start by subtracting the digit 5 and the borrow 1 from 3 in column 4 and get -3.
We add -3 to 10 and get 7 as the next digit of the result.

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

So, 83509 - 5539 = 77970.