Adam went into Watson’s to make a purchase. He asked the price. “One will cost you $2, eight will cost $2, seventeen will cost $4, and six thousand will cost $8.” “Fine, I want thirty-five,” said Adam. What was he buying, and what did he pay?
He�s buying house numbers. He evidently lives at 35 Elm Street (or some other street, but it�s 35 in any case).
If you�re doing this problem with a class, you can solicit other numbers and you can respond with (and list) the prices. They will eventually discover that there�s a jump between nine ($2) and ten ($4), also between 99 and 100, between 999 and 1000, and so on. Maybe somebody will catch on that it�s about buying digits.