Oliver collected 5 times as many computer games as Darius. When Oliver gave Darius some of his computer games, they each had 9. How many computer games had Oliver given to Darius?
From the second sentence, we know \(o + d = 18\)
From the first sentence, we know \(o = 5d\).
Now, just solve or o and d and see how many games Oliver gave to Darius so they have the same number of games.