On which page of Fahrenheit 451 is this quote on?
"I don't know. We have everything we need to be happy, but we aren't happy. Something's missing. I looked around. The only thing I positively knew was gone was the books I'd burned in ten or twelve years. So I thought books might help."
There are many different editions of Fahrenheit 451, so the page number will depends on publisher, typesetting, print size, and many other factors. In addition, there are abridged copies (such as Reader's Digest editions) and ebook editions, some of which have no page numbers to allow for different screen sizes and software.
In Google Books, the available copy is the 2003 Simon and Schuster edition, scanned for preview. In this edition, the quote above appears on page 78, during the scene where Montag visits Faber and tries to convince him that they could print more books to replace the ones that are being burned. The quote is spoken by Montag, as he tries to figure out why his previously-enjoyable life feels so empty and meaningless; he realizes that the only thing that has changed is that he has burned books, removing them from his life entirely.
In part two the sieve and the sand, Montag remembered an event he had with Faber, an old man he met at the city park. The old man hid something and tried to run but Montag stopped him and they sat down to talk. Montag later found out that Faber was an English professor who worked at a liberal arts college and had a mastery of the language and literature. After their encounter Faber gives Montag his address thinking that he may need it to report him. Montag had stolen a copy of the Bible and had to turn it over to the captain but before he did he tried to make a copy of it in his memory. He later visited Faber at his house with the book to Faber’s amazement. Montag wanted Faber to teach him to understand what he read and it is at this point that Montag explains to Faber his reasons for wanting to read and understand (thus appears the quote in question). Faber afterwards informed him that it is not the books that he really needs but the knowledge they contain.
The phrase can be found on page 39 going by the eBook used and referenced.
I believe it is on page 82