Got it! So, we have 599539 and 63004, and we'll subtract the latter from the former.

Step 1: We'll start by subtracting the digit 4 and the borrow 0 from 9 in column 1 and get 5.
5 is the first digit of our result.

Step 2: We'll start by subtracting the digit 0 and the borrow 0 from 3 in column 2 and get 3.
3 is the next digit of our result.

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

Step 4: We'll start by subtracting the digit 3 and the borrow 0 from 9 in column 4 and get 6.
6 is the next digit of our result.

Step 5: We'll start by subtracting the digit 6 and the borrow 0 from 9 in column 5 and get 3.
3 is the next digit of our result.

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

So, 599539 - 63004 = 536535.