Let's get this math done. We have 78979 and 77080, and we're going to subtract the second number from the first.

Step 1: We'll start by subtracting the digit 0 and the borrow 0 from 9 in column 1 and get 9.
9 is the first digit of our result.

Step 2: We'll start by subtracting the digit 8 and the borrow 0 from 7 in column 2 and get -1.
We add -1 to 10 and get 9 as the next digit of the result.

Step 3: We'll start by subtracting the digit 0 and the borrow 1 from 9 in column 3 and get 8.
8 is the next digit of our result.

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

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

So, 78979 - 77080 = 1899.