Well there is certainly a shortcut I would share but by typing it all out...doesn't seem very efficient. So unfortunately unless you have an ifea for a shortcut you have to do it the *sigh* long way. There are two long ways: Follow the proccess of adding then subtract the whole thing. Or, add first (100 + 98 + 96....) and subtract the rest from the total. Unfortunately I can't do the whole problem right now, but I suggest you use a calculator first and then show your work for the method you choose. The reason for a calculator is to check your answer. But do show your work or whoever teaches you might get a bit angry. :D Good luck, sorry if you were expecting an answer but here is an idea.