Okay, let's tackle this math problem. We're starting with 99735 and subtracting 87297.

Step 1: We'll start by subtracting the digit 7 and the borrow 0 from 5 in column 1 and get -2.
We add -2 to 10 and get 8 as the first digit of the result.

Step 2: We'll start by subtracting the digit 9 and the borrow 1 from 3 in column 2 and get -7.
We add -7 to 10 and get 3 as the next digit of the result.

Step 3: We'll start by subtracting the digit 2 and the borrow 1 from 7 in column 3 and get 4.
4 is the next digit of our result.

Step 4: We'll start by subtracting the digit 7 and the borrow 0 from 9 in column 4 and get 2.
2 is the next digit of our result.

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

So, 99735 - 87297 = 12438.