Alright, let's solve this problem step by step. We have 899101 and 12857, 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 1 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 5 and the borrow 1 from 0 in column 2 and get -6.
We add -6 to 10 and get 4 as the next digit of the result.

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

Step 4: We'll start by subtracting the digit 2 and the borrow 1 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 1 and the borrow 0 from 9 in column 5 and get 8.
8 is the next digit of our result.

Step 6: We'll start by subtracting the digit 0 and the borrow 0 from 8 in column 6 and get 8.
8 is the next digit of our result.

So, 899101 - 12857 = 886244.