OK, let's do this. We've got 77620 and 8924, and we're subtracting the second number from the first.

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 2 and the borrow 1 from 2 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 9 and the borrow 1 from 6 in column 3 and get -4.
We add -4 to 10 and get 6 as the next digit of the result.

Step 4: We'll start by subtracting the digit 8 and the borrow 1 from 7 in column 4 and get -2.
We add -2 to 10 and get 8 as the next digit of the result.

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

So, 77620 - 8924 = 68696.