Calling All Cars!

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.

Calling All Cars!

February 11, 2016

When you drive on a busy road, sometimes the traffic stretches for miles and miles – too many cars to count. And that’s just one chunk of road in some town…try to imagine how many cars are on all the roads in your country! Our friend Abigail T. went even bigger: she asked us, how many cars do we have in the whole world? (and painted a picture of herself riding around in one!) Well, there are more than 1 billion cars out there (1,000,000,000). A million is a thousand thousands, and a billion is a thousand millions, so that’s a huge number. The big driver of that number is the U.S., where there are 240 million cars for just 320 million people. To compare, China has just 78 million cars for more than a billion people. But the car counts in both China and India are growing fast. Some experts think we’ll have 2 billion cars by the year 2020. We hope someone’s making enough tires for them.

Wee ones: If you just count 4 blue cars on the road, what number do you say before 4?

Little kids: If 5 houses on your block each have a 2-car garage, how many cars can they hold together? Count up by 2s!  Bonus: If on the road the 1st car in front of you is red, then the 4th car, then the 7th car…what’s the next red car to keep up the pattern?

Big kids: If people in your city bought 100 new cars this month, but 90 old cars went to the junkyard, how many more working cars are there now than a month ago?  Bonus: If every U.S. car owner had 2 cars of those 240 million, how many of the 320 million Americans would not have a car?

The sky’s the limit: There were 500 million cars in 1986, so it doubled by 2010. If it always takes the same amount of time to double, when will we have 4 billion cars?




Wee ones: 3.

Little kids: 10 (2, 4, 6, 8, 10).  Bonus: The 10th car, since every 3rd car is red.

Big kids: 10 more cars.  Bonus: 200 million people, since only 120 million would have a car.

The sky’s the limit: The year 2058. It took 24 years to double that 1st time. To reach 4 billion, we need to double from 1 to 2 billion, then from 2 to 4 billion. Each of those 2 jumps takes 24 years, for a total of 48 years after 2010.

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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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