OK, let's do this. We've got 787688 and 3286, and we're subtracting the second number from the first.

Step 1: We'll start by subtracting the digit 6 and the borrow 0 from 8 in column 1 and get 2.
2 is the first digit of our result.

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

Step 3: We'll start by subtracting the digit 2 and the borrow 0 from 6 in column 3 and get 4.
4 is the next digit of our result.

Step 4: We'll start by subtracting the digit 3 and the borrow 0 from 7 in column 4 and get 4.
4 is the next digit of our result.

Step 5: We'll start by subtracting the digit 0 and the borrow 0 from 8 in column 5 and get 8.
8 is the next digit of our result.

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

So, 787688 - 3286 = 784402.