Dave buys 8 books + 6 books + 3 books = <<8+6+3=17>>17 books in total.

He has to spend 17 books × $6/book = $<<17*6=102>>102 if he wants to buy all the books.

# Answer

102
<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Dave bought 8 books about animals, 6 books about outer space, and 3 books about trains to keep him busy over the holidays. Each book cost $6. How much did Dave spend on the books?
Please reason step by step, and put your final answer within \boxed{{}}.<|im_end|>
<|im_start|>assistant

user
102
Dave bought 8 books about animals, 6 books about outer space, and 3 books about trains to keep him busy over the holidays. Each book cost $6. How much did Dave spend on the books?
train