Welcome to the Playful Math Education Blog Carnival featuring the amazing prime number 131, whose digits can mutate into other prime numbers right before your eyes!

41 + 43 + 47 = 131.

**65**in BASE 21 and

**56**in BASE 25.

We have many different attractions this month. You can go to any category quickly here:

### Carnival Attractions:

Arithmetic

Reading the Comics, September 12, 2019: This Threatens To Mess Up My Plan Edition https://t.co/lZEv7zetVV pic.twitter.com/RyQNYN2Vbu

— Joseph Nebus (@nebusj) September 15, 2019

Arithmetic is also television’s Lisa Simpson’s favorite subject in school and she will miss it greatly as she recovers from the mumps. In this blog post, Safi explains Dr. Hibbert’s comforting words to her about polygons, hypotenuses, and Euclidean algorithms.

### Art

You can always count on Robert Loves Pi to produce a beautiful and complex geometric design. This one he calls Two Rhombic Polyhedra with Tessellated Faces. Here’s another one:

Rings of Pentagons https://t.co/eSekNKVKJv pic.twitter.com/ubjJ6fPoiP

— RobertLovesPi (@RobertLovesPi) September 21, 2019

Paula Beardell Krieg helped students create big, beautiful geometric artwork and origami in Summer Projects with Teens.

— Paula Beardell Krieg (@PaulaKrieg) August 29, 2019

Also, check out Paula’s Paper, Books, and Math Workshop for many more ways to learn math through art.

### Big Prize, Little Chance of Winning

Several years ago Mental Floss wrote about carnival games that offer big prizes but have very little chance of being won. This carnival has a couple of those as well. They are called unsolved math problems. Even if winning probably isn’t going to happen, that doesn’t mean the games and activities aren’t fun. Explaining Science updates us on a very famous unsolved problem, The Goldbach’s Conjecture. Supercomputers have worked on it, but we are no closer to a solution.

In A Neat Unsolved Problem in Number Theory That Kids Can Explore, Mike’s Math Page explores the new-to-me Collatz conjecture that for every positive n, the sum 3 + 8n will equal a perfect square plus an even number. It’s a simple enough conjecture for kids to understand and it is fascinating, yet mathematicians have not been able to prove or disprove it yet!

### Creative Writing

Subha laxmi Moharana (Angel Subu) writes creatively about some tough topics in high school mathematics in Math Poem. I think her words could be turned into a rap.

Poetrywithmathematics shares Doug Norton’s lovely mathematical poem Take a Chance on Me.

What if graphs were self-conscious about their looks? High School aged students can consider that thought as they read the imaginative blog post, To Infinity and Beyond.

### Displays

There’s a cozy classroom place that promotes mathematics in Our New Math Space. It was designed for older students by Continuous Everywhere But Differentiable Nowhere and includes many pictures.

Have you considered displaying a weekly math joke? MathEqualsLove shares a fun joke and a puzzle for kids to gather around and enjoy.

### Factoring Quadratics

How (not) to factorise quadratics with a coefficient greater than 1 https://t.co/iTsbo2q2jK pic.twitter.com/vm2kTDqEfS

— Ben Rooney (@benjrooney) September 14, 2019

Super Safi uses another episode from the Simpsons to teach about the quadratic formula.

### Food for Thought

— Ben Orlin (@benorlin) September 11, 2019

### Games

Joyful Parenting made a simple kindergarten-age counting game and called it Snack Math, but even older kids might enjoy figuring out exactly how many crackers are required to play the game.

How many are in the jar. What is a good estimate? Add Steve Wyborney’s clues one by one to get an even better estimate. He has 51 New Esti-Mysteries that also happen to teach several different math concepts.

Brand New Post!

I’m giving away 51 (fifty-one!) brand new Esti-Mysteries in this blog post: https://t.co/GOq86tk36b

The first ones are are ready to download – and I’ll keep adding many more in the weeks to come. #mtbos #iteachmath #edchat #teaching #learning #math #maths pic.twitter.com/A2pZPupp4H

— Steve Wyborney (@SteveWyborney) September 23, 2019

For older students, Kent Haines a free game he calls Last Factor Loses. I played it a few times with a student. Making prime factorization a game really did make it more fun.

### Geometry

This Puzzle Defeated 96% of the Top Maths Students in the USA

Clue and answer found here: https://t.co/GMphf3tmKU #Puzzle #Puzzles #PuzzleADay #PuzzleForToday pic.twitter.com/CYARuNKH6X

— Puzzle a Day (@PuzzleADayBlog) September 5, 2019

Bn11nb enjoys the geometry of architecture. The pictures in this post are worth a look and could be an inspiration to your students.

### House of Mirrors (Reflecting on Mathematics Teaching)

We often reflect on the effectiveness of our teaching methods. Sometimes we are advised to require students to use more strategies. We might ask them to notice or wonder about a concept. These two thoughtful posts will certainly give you cause for reflection:

“The More Strategies, the Better?

Noticing and Wondering: A powerful tool for assessment

Robert Kaplinsky shares ten things he’s embarrassed to tell you. Has he been reading your mind and mine?

A big problem in education is that teachers keep their insecurities to themselves for fear of being judged. I wish it wasn’t that way. So, I wrote a list of my 10 biggest educator insecurities and hope it’ll make it easier to talk about.https://t.co/lMYLTshIIB #iteachmath #MTBoS pic.twitter.com/wfc3aB2xOF

— Robert Kaplinsky (@robertkaplinsky) September 17, 2019

### Money

What is your favorite part of a cupcake? What if you could buy just that part? What if you wanted to put a whole cupcake together? How much would that cost? Your child can learn about money and decimals exploring those answers with Mathgeekmama’s Money Math Problems.

Puzzle: The Largest Value in Coins Without Change for $1

Clue and answer found here: https://t.co/VkLlKLqz8a #Puzzle #Puzzles #PuzzleADay #PuzzleForToday pic.twitter.com/tpdheM6kot

— Puzzle a Day (@PuzzleADayBlog) September 9, 2019

### Museum of Mathematics

Beads can be a fun manipulative when learning mathematics. Joseph Nebus has begun his 2019 Mathematics A-Z series by writing about the Japanese abacus. He compares it to a slide rule and the Chinese abacus. He also describes how to use it to add, subtract, and multiply numbers. Students could have some fun using it to understand place value, too.

My 2019 Mathematics A To Z: Abacus https://t.co/90CreE0uGi pic.twitter.com/XuTG0d6ohZ

— Joseph Nebus (@nebusj) September 3, 2019

Life Through a Mathematician’s Eyes is giving museum tours in A History of Mathematics-August. K-12 students could be fascinated by the mathematical relics from the Smithsonian founded in August 1846 as well as the Seven Bridges of Königsberg solved by Euler in August 1735.

A History of Mathematics | August https://t.co/kGEE6EUOT5 pic.twitter.com/r2hh54A1Dq

— Life Through a Mathematician’s Eyes (@lthmath) September 2, 2019

### Pumpkin Patch

Erin of Sixth Bloom’s Pumpkin Math-Preschool Activity will engage your little ones as they learn to count and sort pumpkin-shaped macaroni or candies.

They will also love decomposing numbers using pumpkin seeds and Mathgeekmama’s cute Pumpkin cards.

### Posters

Digital Educators Alliance offers free posters of admirable women in math and related fields:

Free Posters Celebrating Women Role Models in Science, Technology, and Math | A Mighty Girl https://t.co/8Q6KGp3s4n

— IL Digital Educators Alliance (@ideaillinois) September 17, 2019

While Sara Van Derwerf set of 112 New Math Fail Posters will delight students as they notice and wonder about and LEARN from grown-ups’ computing mistakes.

### Puzzles

7Puzzle gives some clues about a 3-digit number. Can you figure out what it is?

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Puzzle: Can You Determine These Strange Symbols?

Clue and answer found here: https://t.co/BYu7oHLhPc #Puzzle #Puzzles #PuzzleADay #PuzzleForToday pic.twitter.com/b54sLfP1ya

— Puzzle a Day (@PuzzleADayBlog) September 11, 2019

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Alan Parr writes about a newspaper puzzle called Evens Puzzles. He suggests that students can make their own and hints that he has thought up several variations of it. I look forward to reading about those!

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An Exciting Puzzle

Today’s puzzle is from @solvemymaths

Clue and answer found here: https://t.co/B5NDcqD5UG #Puzzle #Puzzles #PuzzleADay #PuzzleForToday pic.twitter.com/q9ciigkZtv— Puzzle a Day (@PuzzleADayBlog) September 3, 2019

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American Calendars for September had more than a week’s worth of palindromes. Would palindromes make a good puzzle? Yes! Print off a 100 chart and try Denise Gaskins’s A Puzzle for Palindromes. Also, check out her new Morning Coffee feature each week for more math teaching tips.

### Next Month’s Carnival

That’s it for this month’s Math Education Blog Carnival. The 132nd Carnival will be next month at Arithmophobia No More. Would you like to share a post or host the carnival? Go to Let’s Play Math for details!