OK, let's do this. We've got 68853 and 20309, 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 3 in column 1 and get -6.
We add -6 to 10 and get 4 as the first digit of the result.

Step 2: We'll start by subtracting the digit 0 and the borrow 1 from 5 in column 2 and get 4.
4 is the next digit of our result.

Step 3: We'll start by subtracting the digit 3 and the borrow 0 from 8 in column 3 and get 5.
5 is the next digit of our result.

Step 4: We'll start by subtracting the digit 0 and the borrow 0 from 8 in column 4 and get 8.
8 is the next digit of our result.

Step 5: We'll start by subtracting the digit 2 and the borrow 0 from 6 in column 5 and get 4.
4 is the next digit of our result.

So, 68853 - 20309 = 48544.