Okay, let's tackle this math problem. We're starting with 186800 and subtracting 12937.

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

Step 2: We'll start by subtracting the digit 3 and the borrow 1 from 0 in column 2 and get -4.
We add -4 to 10 and get 6 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 2 and the borrow 1 from 6 in column 4 and get 3.
3 is the next digit of our result.

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

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

So, 186800 - 12937 = 173863.