Your Friends’ Friends’ Friends

Here's your nightly math! Just 5 quick minutes of number fun for kids and parents at home. Read a cool fun fact, followed by math riddles at different levels so everyone can jump in. Your kids will love you for it.

Your Friends’ Friends’ Friends

April 29, 2018

Have you ever wondered how many people you know? It’s probably more than you think. You have your family, and all your relatives: grandparents, aunts, uncles, cousins. Then you have your friends and neighbors. That number keeps getting bigger, too: every time you start a new school year, sports team, or art club, you meet new people. Scientists at Columbia University have guessed that American grown-ups each know and remember around 600 people at any time! And of course, if each of them knows 600 people, and each of thosepeople knows 600 people…that’s a lot of friends you could meet.

Wee ones: How many people live in your home, including you?

Little kids: If you go out for ice cream with 9 friends, how many of you are there in total?  Bonus: If each of your friends (but not you) also brings along 1 friend, now how many people go out for ice cream?

Big kids: If you’re counting the 600 people you know, and you’ve counted all but the last one, how many have you counted?  Bonus: If you know 30 people and each of them knows 30 others, how many people come to your party if you invite them all? (Hint if needed: What’s 3 times 30, and then what does 30 x 30 have to be? And don’t forget your own 30 friends…)









Wee ones: Different for everyone…count up your family!

Little kids: 10 people.  Bonus: 19 people, since the friends bring 9 more people.

Big kids: 599.  Bonus: 930, since you have your 30 friends, plus the 30 x 30 who are friends of friends.

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About the Author

Laura Overdeck

Laura Overdeck

Laura Bilodeau Overdeck is founder and president of Bedtime Math Foundation. Her goal is to make math as playful for kids as it was for her when she was a child. Her mom had Laura baking before she could walk, and her dad had her using power tools at a very unsafe age, measuring lengths, widths and angles in the process. Armed with this early love of numbers, Laura went on to get a BA in astrophysics from Princeton University, and an MBA from the Wharton School of Business; she continues to star-gaze today. Laura’s other interests include her three lively children, chocolate, extreme vehicles, and Lego Mindstorms.

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