Pumpkin Face-Off

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.

Pumpkin Face-Off

October 26, 2017

Let’s start with a math riddle: What do you get when you divide the circumference of a jack-o-lantern by its diameter? Answer: Pumpkin Pi! This week it’s time to carve pumpkins to make Halloween jack-o-lanterns. American settlers back in the 1700s carved pumpkins, too, and also made pumpkin pie, simply by dumping milk, honey and spices into the hollowed-out pumpkin and baking it right in the shell. Smart idea, since they could then skip washing all those pots and pans.

Whether you’re turning your pumpkin into a face or a pie, though, you need to scoop out the seeds. A pumpkin holds hundreds of goopy seeds, but bigger pumpkins don’t always have more than smaller ones. Some say you can tell from the ridges on the outside, which line up with the “ribs” inside: more ridges = more ribs = more seeds. So when you’re picking a pumpkin to carve, do a little math up front and you can spare yourself a lot of goop.

Wee ones: What shape are the eyes on this jack-o-lantern?

Little kids: If you carve triangles for the 2 eyes and the nose, how many straight lines have you cut in total?  Bonus: What if you make that nose into a hexagon instead?

Big kids: If your pumpkin has 11 ridges and your friend’s pumpkin has twice as many, how many does your friend’s pumpkin have?  Bonus: If each ridge lines up with a row of 20 seeds, but every 9th ridge starting with the 9th lines up with 100 seeds, how many seeds does the ridgier pumpkin have?




Wee ones: Circles (although not perfect ones).

Little kids: 9 lines or sides.  Bonus: 12 lines: a hexagon has 3 more sides than a triangle.

Big kids: 22 ridges.  Bonus: 600 seeds. Only 2 ridges have 100 seeds apiece. They give us 200 seeds. The remaining 20 ridges give us 20×20 seeds.

And thank you Bedtime Math fan Catherine M. for the math riddle and fun facts! If you’re fan and have a fun topic to share, let us know! Write to feedback@bedtimemath.org.

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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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