Let's get this math done. We have 811589 and 89402, and we're going to subtract the second number from the first.

Step 1: We'll start by subtracting the digit 2 and the borrow 0 from 9 in column 1 and get 7.
7 is the first digit of our result.

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

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

Step 4: We'll start by subtracting the digit 9 and the borrow 0 from 1 in column 4 and get -8.
We add -8 to 10 and get 2 as the next digit of the result.

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

Step 6: We'll start by subtracting the digit 0 and the borrow 1 from 8 in column 6 and get 7.
7 is the next digit of our result.

So, 811589 - 89402 = 722187.