We can solve this together! We're beginning with 21564 and removing 18157 from it.

Step 1: We'll start by subtracting the digit 7 and the borrow 0 from 4 in column 1 and get -3.
We add -3 to 10 and get 7 as the first digit of the result.

Step 2: We'll start by subtracting the digit 5 and the borrow 1 from 6 in column 2 and get 0.
0 is the next digit of our result.

Step 3: We'll start by subtracting the digit 1 and the borrow 0 from 5 in column 3 and get 4.
4 is the next digit of our result.

Step 4: We'll start by subtracting the digit 8 and the borrow 0 from 1 in column 4 and get -7.
We add -7 to 10 and get 3 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, 21564 - 18157 = 3407.