Running Around the Whole World

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.

Running Around the Whole World

November 19, 2015

We’re getting lots of awesome questions here from our fans — thank you all for the cool ideas! Valeria M. in Spain just asked us, how long would it take to run all the way around the world? Believe it or not, a few runners have already done it. This past April, Kevin Carr of England ran around Earth in…can you guess how long it took him? Weeks? Months? Years? He did it in an amazing 621 days (one year has 365 days). Kevin’s trip beat the old world record by just hours: Tom Denniss covered the world in 622 days. That’s a distance of at least 25,000 miles if you ran the biggest possible circle. The question is, what would be the absolute fastest time if a person could run without stopping? Remember, these guys had to sleep, eat, and just rest their feet. Earth is huge, but as we’ll find out below, running without stopping would be way faster!

Wee ones: If you can run 4 miles in an hour and your dog can run 1 mile an hour faster, how fast is your dog?

Little kids: If you run 2 miles from home to the park, then 3 miles more to the ice cream shop, and finally 4 more miles home, how many miles do you run?  Bonus: If you wanted 11 miles total of running, which part of that trip should you run again?

Big kids: If you could run 10 miles an hour for a whole 24-hour day, how many miles would you cover?  Bonus: Then about how many days would it take to run the 25,000 miles around our planet?

The sky’s the limit: If Kevin finished this 621-day run in April 2015, in about what month and year did he start, and how old were you back then? (You can assume 30 days per month, and count from end of April so the 21 days beyond 600 don’t carry you over another month).




Wee ones: 5 miles an hour.

Little kids: 9 miles.  Bonus: From home to the park, since you need 2 more miles.

Big kids: 240 miles.  Bonus: About 100 days.

The sky’s the limit: In August 2013. He took about 20 months from the beginning of April. 12 months takes us to the previous early April, in 2014, and 8 months before that brings us to the previous August. As for your age, that’s different for everyone: August 2013 was 2 years 3 months ago, so subtract 2 years from your age, or 3 years if your birthday is between early August and mid-November!

And thanks again Valeria for keeping us on our toes with the math!

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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 while still in diapers, 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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