Around the World — with the new Bedtime Math book!

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.

Around the World — with the new Bedtime Math book!

June 6, 2017

Today the new Bedtime Math book, How Many Guinea Pigs Fit on a Plane?, comes out in stores — and it answers questions from fans like you! Like our friend Thompson T., who asked, “How many times would the tires on your car turn if you drove around the world once?” As we see in this video, it’s a huge number. A car tire is only about 28 inches wide, which means it’s only about 90 inches around. Earth, on the other hand, is 25,000 MILES around. If you drove around the Earth 10 times, that would be the same as driving all the way to the Moon! Check out the video, then check out the math..and then check out our new book here!

Wee ones: What shape is a car tire?

Little kids: Take a ball of any size, and guess how far it can roll in 1 turn. Now find a spot on the ball, and try it! Was it father or less far than you thought?  Bonus: If a car has 4 tires plus a spare in the trunk, how many tires do 2 cars have together?

Big kids: If you can drive 60 miles an hour nonstop, how far can you drive in 10 days driving 10 hours each day?  Bonus: How many days would it take to finish 1 full 25,000-mile trip around Earth? (Hint if needed: How long would it take to drive 24,000, which divides evenly? And then how many days later will you finish?)

The sky’s the limit — for real: If Earth is about 93 million miles from the Sun, and the distance around a circle is about 3 times its whole width, about how many miles do we travel in a year just sitting on Earth? (You can use pi if you prefer – 3.14.)




Wee ones: A circle, or in 3D, a “torus” (donut shape).

Little kids: We bet it rolls farther than you thought! It will go more than 3 times the width of the ball.  Bonus: 10 tires, since we have 5 + 5.

Big kids: 6,000 miles.  Bonus: 42 days.  You’ll drive the first 24,000 in exactly 40 days, then you’ll need 2 more days to reach 24,600 and finally cross 25,000.

The sky’s the limit: 558 million miles, because to start, the width of the whole circular orbit is 93 million x 2 = 186 million miles.

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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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