<human>:  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 $<human>: Give me more.
<bot>: How many books does Dave buy? ** Dave buys 8 books + 6 books + 3 books = <<8+6+3=17>>17 books in total.
How much does Dave have to spend? ** He has to spend 17 books × $6/book = $<<17*6=102>>102 if he wants to buy all the books.
#### 102