Alright, let's solve this problem step by step. We have 540648 and 99737, and we're subtracting the second number from the first.

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

Step 2: We'll start by subtracting the digit 3 and the borrow 0 from 4 in column 2 and get 1.
1 is the next digit of our result.

Step 3: We'll start by subtracting the digit 7 and the borrow 0 from 6 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 9 and the borrow 1 from 0 in column 4 and get -10.
We add -10 to 10 and get 0 as the next digit of the result.

Step 5: We'll start by subtracting the digit 9 and the borrow 1 from 4 in column 5 and get -6.
We add -6 to 10 and get 4 as the next digit of the result.

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

So, 540648 - 99737 = 440911.