Okay, let's tackle this math problem. We're starting with 94985 and subtracting 66638.

Step 1: We'll start by subtracting the digit 8 and the borrow 0 from 5 in column 1 and get -3.
We add -3 to 10 and get 7 as the first digit of the result.

Step 2: We'll start by subtracting the digit 3 and the borrow 1 from 8 in column 2 and get 4.
4 is the next digit of our result.

Step 3: We'll start by subtracting the digit 6 and the borrow 0 from 9 in column 3 and get 3.
3 is the next digit of our result.

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

Step 5: We'll start by subtracting the digit 6 and the borrow 1 from 9 in column 5 and get 2.
2 is the next digit of our result.

So, 94985 - 66638 = 28347.