No problem, let's work through this together. We're starting with 38878 and are subtracting 21237 from it.

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

Step 2: We'll start by subtracting the digit 3 and the borrow 0 from 7 in column 2 and get 4.
4 is the next digit of our result.

Step 3: We'll start by subtracting the digit 2 and the borrow 0 from 8 in column 3 and get 6.
6 is the next digit of our result.

Step 4: We'll start by subtracting the digit 1 and the borrow 0 from 8 in column 4 and get 7.
7 is the next digit of our result.

Step 5: We'll start by subtracting the digit 2 and the borrow 0 from 3 in column 5 and get 1.
1 is the next digit of our result.

So, 38878 - 21237 = 17641.