I just came across the "Divide 50 by half..." riddle-meme today.
Please don't fall for these. Please don't participate in them. Please just let them die in peace.

- It's a language riddle, not an arithmetic one.
- Specifically, it's a language riddle that tests one of the most difficult, annoying, and subtle parts of most languages: how to use prepositions correctly.
- It's designed to make some people feel smart and others feel stupid, even though intelligence has nothing at all to do with it.