Playful Math Carnival #142: Math Art Edition

Welcome to the 142nd edition of the Playful Math Education Blog Carnival — a smorgasbord of delectable tidbits of mathy fun. It’s like a free online magazine devoted to learning, teaching, and playing around with math from preschool to high school.

Bookmark this post, so you can take your time browsing.

Seriously, plan on coming back to this post several times. There’s so much playful math to enjoy!

By tradition, we start the carnival with a puzzle/activity in honor of our 142nd edition. But if you’d rather jump straight to our featured blog posts, click here to see the Table of Contents.

Activity: Planar Graphs

According to the OEIS Wiki, 142 is “the number of planar graphs with six vertices.”

What does that mean?

And how can our students play with it?

A planar graph is a set of vertices connected (or not) by edges. Each edge links two vertices, and the edges cannot intersect each other. The graph doesn’t have to be fully connected, and individual vertices may float free.

Children can model planar graphs with three-dimensional constructions using small balls of playdough (vertices) connected by toothpicks (edges).

Let’s start with something smaller than 142. If you roll four balls of playdough, how many different ways can you connect them? The picture shows five possibilities. How many more can you find?

Sort your planar graphs into categories. How are they similar? How are they different?

A wise mathematician once said, “Learning is having new questions to ask.” How many different questions can you think of to ask about planar graphs?

Play the Planarity game to untangle connected planar graphs (or check your phone store for a similar app).

Or play Sprouts, a pencil-and-paper planar-graph game.

For deeper study, elementary and middle-school students will enjoy Joel David Hamkins’s Graph coloring & chromatic numbers and Graph theory for kids. Older students can dive into Oscar Levin’s Discrete Mathematics: An Open Introduction. Here’s the section on planar graphs.

[“Geöffneter Berg” by Paul Klee, 1914.]

Click here for all the mathy goodness!

Happy Hamilton Day (Belated)

While searching for posts to add to the Playful Math Carnival, I stumbled on a new-to-me math holiday.

Hamilton Day celebrates mathematical discovery — that “Aha!” moment when your eyes are opened and you see something new.

Or something new-to-you. That’s worth celebrating, too.

History of Hamilton Day

Irish mathematician William R. Hamilton was struggling with a tough math problem in October, 1843. It had him stumped. Then on the 16th, as he walked along Dublin’s Royal Canal with his wife, inspiration struck.

He suddenly realized he could look at the problem from a new direction, and that would make everything fall into place.

“And here there dawned on me the notion that we must admit, in some sense, a fourth dimension of space for the purpose of calculating with triples … An electric circuit seemed to close, and a spark flashed forth.”

—Sir William Rowan Hamilton

In one of the most famous acts of vandalism in math history, Hamilton pulled out a knife and scratched his new equation into the stone of the Broome Bridge: i² = j² = k² = ijk = -1.

Also by Hamilton

“Who would not rather have the fame of Archimedes than that of his conqueror Marcellus?”

—Sir William Rowan Hamilton
quoted in H. Eves, Mathematical Circles Revisited

Why Celebrate Hamilton Day

“So there’s much to celebrate on Hamilton Day. Beyond its utility, we can appreciate mathematics as a human endeavor, with struggles and setbacks and triumphs. We can highlight the opportunity math affords for daring, creativity, and out-of-the-box thinking.

“Hamilton Day could, in other words, pivot away from Pi Day’s gluttony and memorization, neither of which is part of mathematics, toward the intellectual freedom and drama that are.”

— Katharine Merow
Celebrate Hamilton Day, a Better Mathematical Holiday

How Will You Celebrate?

  • Learn about a new-to-you math topic.
  • Work on a tough math problem.
  • Think about different ways to do things.
  • Try a nonstandard approach.
  • Talk about how it feels when you learn something new and it finally makes sense.

I’ve penciled Hamilton Day (October 16) into my calendar for next year.

How about you?

I’d love to hear your ideas for celebrating math! Please share in the comments section below.

 
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This blog is reader-supported.

If you’d like to help fund the blog on an on-going basis, then please join me on Patreon for mathy inspiration, tips, and an ever-growing archive of printable activities.

If you liked this post, and want to show your one-time appreciation, the place to do that is PayPal: paypal.me/DeniseGaskinsMath. If you go that route, please include your email address in the notes section, so I can say thank you.

Which I am going to say right now. Thank you!

“Happy Hamilton Day (Belated)” copyright © 2020 by Denise Gaskins.

Commemorative plaque photo (top) by Cone83, CC BY-SA 4.0. Hamilton portrait by Unknown artist and “Death of Archimedes” by Thomas Degeorge, public domain. All via Wikimedia Commons.

Football as a Game of Fractions

I couldn’t quite figure out how to fit it into the Playful Math Carnival, but this post made me laugh:

“In football, a tie counts as a half-win (and a half-loss). But half-wins are sometimes worth more than half a win, sometimes they’re worth less than half a win, and sometimes they’re worth exactly half a win. Let me ‘splain…”

—Patrick Vennebush
When a Half Is More Than a Half (and When It Ain’t)

 
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This blog is reader-supported.

If you’d like to help fund the blog on an on-going basis, then please head to my Patreon page.

If you liked this post, and want to show your one-time appreciation, the place to do that is PayPal: paypal.me/DeniseGaskinsMath. If you go that route, please include your email address in the notes section, so I can say thank you.

Which I am going to say right now. Thank you!

“Football as a Game of Fractions” copyright © 2020 by Denise Gaskins. Image at the top of the post copyright © Dave Adamson via Unsplash.com.

Working on the Playful Math Carnival

Every time I put together a Playful Math Education Blog Carnival, it becomes my favorite blog post of all time.

At least until the next edition.

I’m always delighted by the posts I discover. There’s so much richness in the math blogging community. This month’s carnival is no different.

I think you’re going to love it!

Hint of Things to Come

The Paul Klee painting above is from the carnival. Isn’t it beautiful?

In the carnival post, I use the image to complement a math activity about graphs.

But I think it’s also a wonderful reminder of how connections (between individual bloggers or between math topics in a carnival) make a richer whole than any of us could create on our own.

Would You Like to Help?

We need volunteers! Classroom teachers, homeschoolers, unschoolers, or anyone who likes to play around with math (even if the only person you “teach” is yourself) — if you would like to take a turn hosting the Playful Math Carnival, please speak up!

CREDITS: “Geöffneter Berg” by Paul Klee, 1914 via John Golden’s (Mathhombre) Miscellanea.

The Gerrymander Math Project

With a big election on the horizon, now is a great time to talk about the math of politics.

Does “One person, one vote” make a fair democracy?

Or does it give the majority license to trample a minority?

How can planners arrange voting districts to give everyone the best representation? And is that really what politicians would do, if they had the choice?

Try the Gerrymander Project with your students to investigate these questions and spark real-world mathematical discussion.

First, Create a Map

[Or buy a copy of my printable activity guide, The Gerrymander Project: Math in the World of Politics, which includes a prepared city map with more detailed instructions, answers, and journaling prompts. My publisher has extended the 10% discount code TBLTOP10 through to Election Day, 3 November 2020.]

  • Print a blank hundred chart or outline a 10×10 square on grid paper. This represents your city. Give it a name.
  • Pull out your colored pencils. Choose one color for your city’s Majority Party and another for the Minority Party.
  • Color 10 squares in a neutral color for non-voting areas. These might be malls or parks or the downtown business district — your choice.
  • Color the remaining 90 blocks in a random distribution so that 60% are the Majority color and 40% the Minority. How will you choose which squares to make which colors? Can you think of a way to use dice or playing cards to make your choices random, yet still get the right proportion?

Slip your finished map into a clear page protector, so you can mark on it with dry-erase markers. Or make several copies, so you can write on them without destroying the original.

Then Gerrymander Your City

“Gerrymandering” is the American political tradition of adjusting the voting district boundaries to favor one’s own party at the expense of one’s opponents.

The city has hired you to mark out 10 new voting districts of 9 squares each (not counting the neutral squares, which can go in any district). The squares in each district must touch side-to-side, not just meet at a corner.

So now you get to play “political hack.”

First, see how fair you can make the map:

  • What happens if you ignore the party colors and make your districts as compact as possible, so the people living nearest to each other vote together? Will the Majority Party always win?
  • Can you give all your voters a proportional representation? Both parties should win the number of districts that most closely matches their percentage of the voting population.

Next, try your hand at gerrymandering, but make sure all the squares in each district stay connected. Can you create ten voting districts that will guarantee:

  • A come-from-behind triumph for the Minority Party? They need to carry at least six districts to wrest control of the City Council from their opponents.
  • The greatest possible margin of victory for the Majority Party? Can you keep the Minority from winning any districts at all?

Share Your Thoughts

I’d love to hear your students’ reaction to this project. Please share in the comments section below.

For myself, the more I play with this project, the more I admire the work done by the framers of the U.S. Constitution. Our Electoral College divides the country into “districts” based on state boundaries, giving each a vote roughly proportional to its population — but in a way that slightly strengthens the Minority Party. The system may not be perfect, but it’s done an amazing job through the centuries of maintaining a balance of power, making sure that neither major political party can destroy the other.

Which is NOT to say that our country always protects the rights of true minorities. Clearly, that’s an ongoing struggle.

But overall, the political parties stay relatively balanced, making for a stable government. After more than two centuries, we still have, as Ben Franklin said, “a republic, if you can keep it.”

 
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This blog is reader-supported.

If you’d like to help fund the blog on an on-going basis, then please head to my Patreon page.

If you liked this post, and want to show your one-time appreciation, the place to do that is PayPal: paypal.me/DeniseGaskinsMath. If you go that route, please include your email address in the notes section, so I can say thank you.

Which I am going to say right now. Thank you!

“The Gerrymander Math Project” copyright © 2020 by Denise Gaskins.

More Math War with Special Decks

Just updated my blog post Math Game: War with Special Decks to add a couple of games I missed the first time around:

And…

If you’d like more ways to play with math from preschool to high school, check out My Favorite Math Games.

 
* * *

This blog is reader-supported.

If you’d like to help fund the blog on an on-going basis, then please join me on Patreon for mathy inspiration, tips, and an ever-growing archive of printable activities.

If you liked this post, and want to show your one-time appreciation, the place to do that is PayPal: paypal.me/DeniseGaskinsMath. If you go that route, please include your email address in the notes section, so I can say thank you.

Which I am going to say right now. Thank you!

“More Math War with Special Decks” copyright © 2020 by Denise Gaskins. “Red playing cards” photo by José Pablo Iglesias via Unsplash.com.

Prealgebra & Geometry Preorders

Math You Can Play series by Denise Gaskins

My book Prealgebra & Geometry: Math Games for Middle School is scheduled for release to regular bookstores in February, 2021. Because no publisher wants to send a new book into the world during such hectic, unsettled times as a big election, the winter holidays, or during inauguration season.

But preorder links are beginning to appear at several of the major online booksellers. And more stores will join them, as the information filters through their website systems.

The paperback will also be up for preorder, whenever the sites catch that update.

And remember: If you don’t favor a particular bookstore, you can buy the early-release ebook right now at my publisher’s webstore — and get a 10% discount if you order before 15 October.

Math Journals for Kids and Adults

Journaling is a fantastic way to learn and remember any topic — including math. That’s why I created my dot grid journals for kids and adults.

But I just discovered that my printer hates journals and blank books. They refuse to publish them any more.

How frustrating!

So from now on, you can only get my math journals from Amazon. The largest-river-in-the-world store doesn’t mind dot grid pages (so far).

Silver Lining: Because the books aren’t available to regular bookstores, I don’t have to allow for the traditional bookstore discount. Which means I can cut the prices. By a LOT — the new prices are 30% off the original cost of the books!

Continue reading Math Journals for Kids and Adults

Parallel and Perpendicular Art

I love this easy-but-beautiful math art project!

1. Print a page of dotty or lined graph paper for each student. You’ll also need a ruler and a large assortment of markers or colored pencils.

2. Students draw a line across the page, lining up their ruler with the grid points. The first line can be vertical, horizontal, or diagonal.

3. Keep drawing lines, but NEVER cross a line you’ve already drawn. Following the grid will create many lines parallel or perpendicular to each other. What angles can you identify?

4. Color as desired. For a stained-glass effect, outline the colored areas with a black Sharpie marker.

Look for more math art ideas in my new book Geometric Coloring Designs 2: Create Your Own Art.

CREDITS: I saw this project at Cindy’s Love2Learn2Day blog. She got the idea from Zachary‘s MathActivities site.

I Love Fall! Here’s a Special Offer to Celebrate

Summer’s gone, and the beautiful, brisk days of harvest season have arrived in all their glory.

Fall is definitely my favorite time of year.

This fall, my publishing company opened a store where you can buy direct from us. When you choose to cut out the middleman, we authors get paid 50% more royalties. Thank you for your support!

You get a bonus, too: When you buy direct from our online store, you get DRM-free ebook files in your choice of format — including printable pdf files not available in bookstores. And if you need help, our friends at BookFunnel will be more than happy to walk you through the steps of transferring ebook files to your phone or device.

Best of all, you can pick up the exclusive publisher’s-edition ebook of my long-awaited Prealgebra & Geometry: Math Games for Middle School (scheduled for publication to regular bookstores in February 2021).

So even if you missed the Kickstarter, you won’t miss out on playing math with your middle-school kids this fall.

Special Offer: Use the coupon code TBLTOP10 at checkout to save 10% off your purchase. (Expires 15 October 2020.)

Click Here to Shop Our Online Store