We can calculate our age in dog years, so why not Leap Day years? Unlike the canine formula — anyone can multiply their age by 7 to get the answer — the Leap Day math applies to people born on Feb. 29 ...

Your support goes further this holiday season. When you buy an annual membership or give a one-time contribution, we’ll give a membership to someone who can’t afford access. It’s a simple way for you ...

Are you smarter than a really smart Singapore high school student? See if you can figure out Cheryl’s birthday, the Singapore logic problem that’s got the Internet twisted into knots. Some are even ...

A math problem intended to identify the top 40% of students has become the obsession of the Internet. The seemingly simple question: ‘When is Cheryl’s birthday?’ You can save this article by ...

Can you figure out when Cheryl’s birthday is? A puzzling logic problem for middle school “mathletes” in Singapore has gone viral online. After a television host in Singapore posted the question to his ...

Hal and Carol accept an invitation to a house party. Hal sees that there will be 30 people attending the party and says to Carol, “I bet you $100 that at least two people will have the same birthday ...