Alright, ready to do some subtraction? We're taking 20337 and subtracting 18156 from it.

Step 1: We'll start by subtracting the digit 6 and the borrow 0 from 7 in column 1 and get 1.
1 is the first digit of our result.

Step 2: We'll start by subtracting the digit 5 and the borrow 0 from 3 in column 2 and get -2.
We add -2 to 10 and get 8 as the next digit of the result.

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

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

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

So, 20337 - 18156 = 2181.