I recently finished reading How to Eat Fried Worms with Sam and Caroline. I remember it being one of the first chapter books I read myself. Sam and Caroline seemed to enjoy it though the book at times seemed somewhat dated. I found this page from late in the book fairly interesting.
The book's publication date is 1973. In the 1970s, most kids would've gotten the reference contained in this chapter title. If they didn't, dads or moms would be able to supply the answer. Pearl Harbor was as immediate in the cultural memory of those days as 9/11 is today.
The bet Billy wins (sorry, spoiler) is for $50. In today's dollars that is $268.30. No wonder the boys resort to the schemes and tricks to which they resort in the book.
That night at the ballpark costs $8, which today is $42.93. Assuming that the $8 doesn't include the ticket, that is actually pretty close to correct. a 12-year-old could get stuffed on about $40 worth of ballpark food today or in 1973.