Jimmy has 18 cards. Jimmy gives three cards to Bob. If Jimmy gives Mary twice as many cards as he gave to Bob, how many cards does Jimmy have left? Let's be accurate as possible.

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
Mary has 2 * 3 = 6 cards. Jimmy has 18 - 3 - 6 = 9 cards left.
The answer: 9.