Pi Day of the Century!

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.

Pi Day of the Century!

March 14, 2015

It’s Pi Day, and today is the Pi Day of the century! Why? If you cut a string that’s the width of a circle, then wrap that string around the edge of that circle, you’ll need a little more than 3 of that string to reach all the way around. The exact number comes to 3.14159265… (it goes on and on for thousands of digits). March 14, when written as 3/14, looks like the start of that number, and this year matches even better because it’s 3/14/15! We use pi every day without even realizing it. If you wrap a measuring tape around your head, then take that length in inches and divide by pi, you’ll get the width of your head — and that’s also your hat size! Pi also tells you how many bike-tire widths the wheels have to roll to make one full turn. And when you bake a pie, the width of it tells you how much crust you’ll need around the edge…but you’ll have to decide how much of that you can actually eat.

Wee ones: What things in your house are circles? How many can you see?

Little kids: If you slice one pie into 6 slices and another same-size pie into 8 slices, which pie has bigger slices?  Bonus: How many slices do the 2 pies have in total?

Big kids: If your head is 22 inches around, about what hat size do you have?  Bonus: If your bike has 2-foot wide tires and you ride far enough for them to turn 10 times, how many feet did you drive? (You can round pi to 3 if you like, or use 3 1/7, or try 3.14!)




Wee ones: Different for everyone…clocks, plates and cups, and Frisbees are just a few!

Little kids: The slices from the 6-slice pie are bigger: you cut fewer, so each has more pie in it.  Bonus: 14 slices.

Big kids: About size 7.  Bonus: The tire is about 6 feet around (or 6 1/7, or 6.28), so you ride about 60 feet (or 60 and 10/7, which is 61 3/7…or 62.8 feet).

And thank you Mary Claire A. for throwing your hat in the ring and sharing this topic!

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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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