How to do long division with remainders 780 : 8?

Well, breaking it down, you're going to do 780/8, in two/three steps.

First, you'll do 78/8, which is 9. 78 - (8*9) is now

78-72 = 7.

Then, we're going to take the 0 and put that at the end of 7, making it 70

so 70/8 is 8, with 6 left over.

Now we smoosh these numbers together to get 96 remainder 6