We can solve this together! We're beginning with 7874 and removing 7128 from it.

Step 1: We'll start by subtracting the digit 8 and the borrow 0 from 4 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 2 and the borrow 1 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 1 and the borrow 0 from 8 in column 3 and get 7.
7 is the next digit of our result.

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

So, 7874 - 7128 = 746.