Have you ever seen one of your own hairs on your sweater or hairbrush? We “shed” hair, meaning a few hairs fall out every day because they’re done growing. We shed between 50 and 100 head hairs each day! (Don’t worry — new hairs grow back in). Mammals all have hair, even elephants and kangaroos, and they all shed, too. So our friend Jakub J.asked, if a cat gets $1 for each hair it sheds, how rich would it be in 1 day, 1 month, and 1 year? Our furry friends have FAR more hair than we do: we have about 100,000 on our head, while a cat might have about 40 MILLION hairs on its body. If we lose 100 of our 100,000 every day, that’s 1 hair out of every thousand…so how many would that be for a cat? Let’s figure it out!
Wee ones: Hold some hair in your fingers. Now try to hold just 2 of those hairs, and let the rest go!
Little kids: Hold a hair straight up from the top of your head. About how long is it in inches? Ask a grown-up to help you guess, or use a ruler! Bonus: If you lose 50 hairs one day and 10 more then next, how many do you lose the 2nd day?
Big kids: How do you “spell” 40 million as a number? Bonus: If the cat loses 1/1000th of those hairs in a day, how many hairs is that – and how many dollars if he gets $1 for each? Then estimate for 1 month and 1 year! (Hint if needed: To divide by 1,000, you take 3 zeroes off the end of the number.)
Wee ones: Try to pinch just 2 hairs.
Little kids: Different for everyone…it could be anywhere from half an inch to many inches. Bonus: 60 hairs.
Big kids: 40,000,000. Bonus: $40,000 in one day! In a 30-day month that cat would earn $1,200,000 (more than a million dollars), and in 12 months of about that length, it would earn $14,400,000.
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.