No problem, let's work through this together. We're starting with 21304 and are subtracting 1855 from it.

Step 1: We'll start by subtracting the digit 5 and the borrow 0 from 4 in column 1 and get -1.
We add -1 to 10 and get 9 as the first digit of the result.

Step 2: We'll start by subtracting the digit 5 and the borrow 1 from 0 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 1 and the borrow 1 from 1 in column 4 and get -1.
We add -1 to 10 and get 9 as the next digit of the result.

Step 5: We'll start by subtracting the digit 0 and the borrow 1 from 2 in column 5 and get 1.
1 is the next digit of our result.

So, 21304 - 1855 = 19449.