Oliver had $9, then he saved $5 from his allowance and spent $4 on a frisbee and $3 on a puzzle. His friend gives him another $8 as it's his birthday. How much money does Oliver have left? Let's answer step by step:

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
The total amount of money saved is $9 + $5 = $14. The total cost of the frisbee and the puzzle is $4 + $3 = $7. So Oliver has $14 - $7 = $7 left. His friend gives him $8, so now he has $7 + $8 = $15. The answer: 15.