Alright, ready to do some subtraction? We're taking 18315 and subtracting 12875 from it.

Step 1: We'll start by subtracting the digit 5 and the borrow 0 from 5 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 1 in column 2 and get -6.
We add -6 to 10 and get 4 as the next digit of the result.

Step 3: We'll start by subtracting the digit 8 and the borrow 1 from 3 in column 3 and get -6.
We add -6 to 10 and get 4 as the next digit of the result.

Step 4: We'll start by subtracting the digit 2 and the borrow 1 from 8 in column 4 and get 5.
5 is the next digit of our result.

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

So, 18315 - 12875 = 5440.