Alright, ready to do some subtraction? We're taking 890823 and subtracting 99973 from it.

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

Step 2: We'll start by subtracting the digit 7 and the borrow 0 from 2 in column 2 and get -5.
We add -5 to 10 and get 5 as the next digit of the result.

Step 3: We'll start by subtracting the digit 9 and the borrow 1 from 8 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 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 9 in column 5 and get -1.
We add -1 to 10 and get 9 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, 890823 - 99973 = 790850.