Millions of People Can’t Solve this Math Word Problem. Can You?

The math problem, “When is Cheryl’s Birthday?” has gone viral.  A google search generated 251 news articles about it in one day.  Some of the headlines included:

“The (Solvable) Math Problem that will Break your Brain”

“Forget the Common Core.  Can you Figure out Cheryl’s Birthday?”

“The Logic Problem that Blew up the Internet”

What’s all the fuss about?  Here’s the problem (I’ll get to the answer in a minute):

Albert and Bernard just met Cheryl. “When’s your birthday?” Albert asked Cheryl.

Cheryl thought a second and said, “I’m not going to tell you, but I’ll give you some clues.” She wrote down a list of 10 dates:

May 15, May 16, May 19

June 17, June 18

July 14, July 16

August 14, August 15, August 17

“My birthday is one of these,” she said.

Then Cheryl whispered in Albert’s ear the month — and only the month — of her birthday. To Bernard, she whispered the day, and only the day.

“Can you figure it out now?” she asked Albert.

Albert: I don’t know when your birthday is, but I know Bernard doesn’t know, either.

Bernard: I didn’t know originally, but now I do.

Albert: Well, now I know, too!

When is Cheryl’s birthday?

Just reading it makes your head hurt, right?

I’m a Math geek, and I love this kind of challenge.  I would begin by using a standard process for finding an answer to any word problem:

  • Read the problem carefully.
  • Figure out what’s known and what needs to be found out.
  • Try a few numbers to get an idea of what the solution would be.
  • Write an equation, and
  • Solve by inverse operations or plugging in values.

Still, Cheryl’s Birthday would take me a long time to figure out.  Rather than go into the details here, check out the solution in this video.

As hard as it is to find out when Cheryl was born, crazy word problems like this can help your child be more successful in life.  Sounds like a stretch, I know.

But word problems help students gain skills that make them more logical and creative – two attributes of people who get ahead in life.  More important, when students attempt a difficult problem, and you encourage them not to give up, they learn perseverance.

In a previous blog post, I discussed why perseverance – also known as “Grit” – is the most important characteristic a child can have to be successful.

Miracle Math Coaching is an excellent resource for teaching your children to persevere.  Call me directly at 707-398-3474, ext. 2700 to learn more.  Or sign up for a free assessment to get started right away. Miracle Math Coaching is an award-winning, student-focused service with a track record of boosting academic achievement.


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