Let's dive into this subtraction. We'll start with 68401 and subtract 278 from it.

Step 1: We'll start by subtracting the digit 8 and the borrow 0 from 1 in column 1 and get -7.
We add -7 to 10 and get 3 as the first digit of the result.

Step 2: We'll start by subtracting the digit 7 and the borrow 1 from 0 in column 2 and get -8.
We add -8 to 10 and get 2 as the next digit of the result.

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

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

Step 5: We'll start by subtracting the digit 0 and the borrow 0 from 6 in column 5 and get 6.
6 is the next digit of our result.

So, 68401 - 278 = 68123.