Okay, let's tackle this math problem. We're starting with 85881 and subtracting 79770.

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

Step 2: We'll start by subtracting the digit 7 and the borrow 0 from 8 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 8 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 5 in column 4 and get -4.
We add -4 to 10 and get 6 as the next digit of the result.

Step 5: We'll start by subtracting the digit 7 and the borrow 1 from 8 in column 5 and get 0.
0 is the next digit of our result.

So, 85881 - 79770 = 6111.