Sure thing! We've got 6451 and 4001, and we're going to subtract the second number from the first.

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

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

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

Step 4: We'll start by subtracting the digit 4 and the borrow 0 from 6 in column 4 and get 2.
2 is the next digit of our result.

So, 6451 - 4001 = 2450.