This may be simple but I want to see a formula and admit I've been out of school too long to figure this one out. Although it's bugging me! I would like to see a formula, too, not just the answer. So you have 6 items. For example ABCDEF. You must use at least one item. Order does not matter (ie. ABC=ACB) They can not repeat. So how many different combinations can I create with these items? Thanks in advanced!