Your Miles and Miles of Hair

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 Miles and Miles of Hair

December 1, 2014

Every day, every hair on your head grows. It grows just a little bit, about ½ inch in a whole month, but that’s more than zero. And remember, you have around 100,000 hairs on your head. So how much hair in total do you grow every day? That’s 50,000 inches a month, or almost 4,200 feet…nearly a mile of hair every month! That’s just your head, too: like all other mammals, you have hair on every part of your body, except for your lips, the flats of your eyelids, the palms of your hands, and the bottoms of your feet. When you figure out all that hair growth for a year, or for your whole life, you see that while you’re eating, sleeping, running, playing soccer, or whatever else you do, you’re also a crazy hair-making machine.

Wee ones: Can you count out 5 hairs on your head with your fingers? (without pulling them out!) What do 5 hairs feel like together?

Little kids: If your hair is 8 inches long right now and you let it grow 2 inches, how long will it be then?  Bonus: If your hair is 5 inches long right now and you have 100,000 hairs, how much hair do you have on your head right now?

Big kids: If you’ve been growing 11 miles of hair a year, how much hair have you grown in your life?  Bonus: If you grow 42,700 inches of hair each month, how many feet do you grow in a year? See if you can figure out the shortcut!




Wee ones: Count 1, 2, 3, 4, 5.

Little kids: 10 inches.  Bonus: 500,000 inches, which happens to be almost 8 miles of hair.

Big kids: Different for everyone…multiply your age in years by 11 (you can also add in 1/2-years, 1/4-years, or months if you like).  Bonus: 42,700 feet, because you divide by 12 to get feet, then multiply by 12 for the 12 months!

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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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