We call this the '24' game.

If someone can solve this one I'd be obliged.

7, 8, 8, 9

(or maybe it's 7, 7, 8, 9 or 7, 8, 9, 9 one of those. those three numbers and one's done twice)
________________________________

We used to play it in fifth grade all the time. Had a contest for it. We'd draw a card that had four numbers on it and would race to solve it. the 7 8 9 one was the only one I don't ever remember being able to solve.

(6, 6, 6, 6 was the easiest, for shizzle.)