OK, let's do this. We've got 600679406 and 346014080, and we're subtracting the second number from the first.

Step 1: We'll start by subtracting the digit 0 and the borrow 0 from 6 in column 1 and get 6.
6 is the first digit of our result.

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

Step 4: We'll start by subtracting the digit 4 and the borrow 0 from 9 in column 4 and get 5.
5 is the next digit of our result.

Step 5: We'll start by subtracting the digit 1 and the borrow 0 from 7 in column 5 and get 6.
6 is the next digit of our result.

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

Step 7: We'll start by subtracting the digit 6 and the borrow 0 from 0 in column 7 and get -6.
We add -6 to 10 and get 4 as the next digit of the result.

Step 8: We'll start by subtracting the digit 4 and the borrow 1 from 0 in column 8 and get -5.
We add -5 to 10 and get 5 as the next digit of the result.

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

So, 600679406 - 346014080 = 254665326.