We can solve this together! We're beginning with 89784 and removing 78073 from it.

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

Step 2: We'll start by subtracting the digit 7 and the borrow 0 from 8 in column 2 and get 1.
1 is the next digit of our result.

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

Step 4: We'll start by subtracting the digit 8 and the borrow 0 from 9 in column 4 and get 1.
1 is the next digit of our result.

Step 5: We'll start by subtracting the digit 7 and the borrow 0 from 8 in column 5 and get 1.
1 is the next digit of our result.

So, 89784 - 78073 = 11711.