Got it! So, we have 39742 and 21546, and we'll subtract the latter from the former.

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

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

Step 3: We'll start by subtracting the digit 5 and the borrow 1 from 7 in column 3 and get 1.
1 is the next digit of our result.

Step 4: We'll start by subtracting the digit 1 and the borrow 0 from 9 in column 4 and get 8.
8 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, 39742 - 21546 = 18196.