Imagine you’re at a party. There are 23 people in the room, including you. Someone proposes a bet: “I bet at least two people here share the same birthday.” You do the mental math. With 365 days in a ...

How many people need to be in a room before there's a greater probability than chance that two of them share a birthday? Numberphile approaches the famous birthday paradox without a computer.

DEAR MISS MANNERS: My birthday is a few days after the new year. It’s a very easy date to miss altogether in the shadow of December and New Year’s celebrations. Miss Manners: It’s a problem when his ...