No problem, let's work through this together. We're starting with 6920 and are subtracting 254 from it.

Step 1: We'll start by subtracting the digit 4 and the borrow 0 from 0 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 5 and the borrow 1 from 2 in column 2 and get -4.
We add -4 to 10 and get 6 as the next digit of the result.

Step 3: We'll start by subtracting the digit 2 and the borrow 1 from 9 in column 3 and get 6.
6 is the next digit of our result.

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

So, 6920 - 254 = 6666.