No problem, let's work through this together. We're starting with 63539 and are subtracting 6670 from it.

Step 1: We'll start by subtracting the digit 0 and the borrow 0 from 9 in column 1 and get 9.
9 is the first digit of our result.

Step 2: We'll start by subtracting the digit 7 and the borrow 0 from 3 in column 2 and get -4.
We add -4 to 10 and get 6 as the next digit of the result.

Step 3: We'll start by subtracting the digit 6 and the borrow 1 from 5 in column 3 and get -2.
We add -2 to 10 and get 8 as the next digit of the result.

Step 4: We'll start by subtracting the digit 6 and the borrow 1 from 3 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 0 and the borrow 1 from 6 in column 5 and get 5.
5 is the next digit of our result.

So, 63539 - 6670 = 56869.