Welcome to the sweet-16 birthday edition of the Playful Math Carnival. Originally called Math Teachers at Play, our first carnival was published in February 2009.
Each Playful Math Carnival offers 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.
There’s so much playful math to enjoy!
By tradition, we start the carnival with a math activity in honor of our 179th edition. But if you’d rather jump straight to our featured blog posts, click here to see the Table of Contents.
NOTE: Our wonderful volunteer hosts have kept the Playful Math Carnival going when so many other blog carnivals died off. If you’d like to sign up to host the carnival for a month, email Denise for information.
Try These Prime Puzzles
Did you know there are 179 even-numbered days this year?
- How many even-numbered days will there be in a leap year?
- But there are 365 days in a standard year and 366 in a leap year. Shouldn’t there be half that many even-numbered days?
179 is a prime number, and it’s also a knockout prime. You can knock out any of the digits, and what’s left is still prime: 17, 19, or 79.
- Can you find another knockout prime number?
179 is a twin prime. That means that one of its odd-numbered neighbors is also prime.
- Is the other twin 177 or 181? Can you tell without looking it up?
- Why are twin primes limited to the odd numbers? That doesn’t seem fair!
179 is also an emirp. That’s a special kind of prime that forms a different prime number when you write it backwards: 971 is also prime.
- How many emirps can you find?
“A palindrome is a word that when written in reverse results in the same word. for example, ‘racecar’ reversed is still ‘racecar’. Related to palindromes are semordnilaps. These are words that when written in reverse result in a distinct valid word. For example, ‘stressed’ written in reverse is ‘desserts’. Not all words are palindromes or semordnilaps.
“While certainly not all numbers are palindromes, all non-palindromic numbers when written in reverse will form semordnilaps.
“Narrowing to primes brings back the same trichotomy as with words: some numbers are emirps, some numbers are palindromic primes, but some are neither.”
Contents
And now, on to the main attraction: the blog posts. If you’d like to skip directly to your area of interest, click one of these links.
- Exploring Elementary Arithmetic
- Adventuring into Algebra and Geometry
- Scaling the Slopes of High School Math
- Enjoying Recreational Puzzles and Math Art
- Teaching with Wisdom and Grace
- Giving Credit Where It’s Due
To celebrate my new Math Journaling Adventures series of student logbooks, each section of the carnival includes a puzzle or activity to get kids playing with and writing about math.
[Puzzle by Play With Your Math blog.]
Exploring Elementary Arithmetic
- Michael Minas teaches two new math games: Tenzi for number recognition, and In The Club (number properties).
- Steve Wyborney shares his pattern-sniffing mystery: Leaping Numbers Season 2.
- Heinrich Hemme posts a multiplication puzzle: Follow the Calculator Clues.
- David Marain poses A ‘Catz’ Conjecture Investigation.
- For my entry to the carnival, a memory: My daughter’s first math proof about negative numbers.
- Howie Hua explains Why we can’t divide by zero.
- Marilyn Burns investigates Comparing and Ordering Decimals with fifth-graders.
- Rupesh Gesota talks math on the train: Math-journey in the Train-journey ~ Part-1 and Part-2.
- Sarah Carter collects a list of Pi Day Jokes.
- John Rowe brings together arithmetic and geometry in Simple, but Rich: Fraction Talk Patterns.
[Puzzle by Play With Your Math blog.]
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Adventuring into Algebra and Geometry
- David Petro introduces linear equations with an Equation Strips activity.
- Henri Picciotto lauds the value of Function Diagrams for algebraic understanding and offers several activities.
- Greg Ross dabbles in shape combinations: Magic Square Hereabouts, and More Geomagic.
- Henri Picciotto shares a variety of Geometric Puzzles for the Classroom.
- Karen Campe continues her Go for Geometry! series on using math technology with Episode 3: Points of Concurrency.
- Can you solve my Puzzle: Patty Paper Trisection?
- For a more advanced approach, Pat Ballew digs into Trisecting an Angle, an Interesting Historical Comparison and a Mystery.
[Puzzle by Play With Your Math blog.]
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Scaling the Slopes of High School Math
- Luke Bordonaro explains the basic concepts of Calculus at a Fifth Grade Level.
- Sam Blatherwick highlights Results with the Unit Circle that are useful at A-level.
- Colleen Young collects activities for playing with Polar Coordinates.
- Alex Velez looks at ways to make your data more readable: An alternative to error bars.
- Tim Corica offers several practical applications in Logarithms: Some teaching ideas.
- Karen Campe shares a link to the High School Rules That Expire along with her February Calendar Problems (which are still fun, even though February is nearly done).
- Erick Lee spices up Calculus review with Add ‘Em Up – Limits. You may also enjoy his Derivative Rules Add Em Up Activity.
- And don’t miss the 236th Carnival of Mathematics.
[Puzzle by Play With Your Math blog.]
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Enjoying Recreational Puzzles and Math Art
- JoAnne Growney shares one of my favorite math poems: Halfway Up . . . Halfway Down. And introduces me to a new favorite: Counting and Rhyming.
- Pam Harris promotes flexible mental math fluency with her weekly #MathStratChat puzzle.
- Pat Ballew investigates and extends the Flipping Pennies trick.
- Steve Walker highlights a new math puzzle every week: #OCRMathspuzzle.
- Desmos blog posts their 2024 Art Expo Gallery of student-created masterpieces.
- John Golden finds a photo of Escher at Work. I didn’t realize his art was so big.
- Greg Ross challenges us to navigate A Number Maze.
- Ben Orlin revises a few math classics: “Find my age” puzzles (but with all true facts).
- Colin Beveridge extends the Hilbert Hotel story: All hands meeting.
- John Golden finds a cool variation on the Penrose triangle: Strange box with hole.
- Douglas Hofstader orchestrates artistic Metamagical Themas.
- Mathical announces their 2025 Mathical Book Prize Winners, with fiction and nonfiction for youth ages 2-18.
- Chalkdust Magazine posts the shortlist of their favourite maths-themed Books of the Year 2024.
- Thony Christie examines Books on the history of mathematics.
[Puzzle by Play With Your Math blog.]
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Teaching with Wisdom and Grace
- Pam Barnhill and I chat about Making Math a Delight and how the cycle of Notice-Wonder-Create builds deep understanding of tough topics.
- Dan Meyer explains Why Individualized Learning Hasn’t Worked.
- Dylan Kane analyzes why some kids struggle to learn algebra: Break It Down. Also, he looks at what makes for A Nice Worksheet.
- Chris Luzniak recognizes the value of clear, specific lesson objectives: What’s the Point?
- Greg Ross offers a humiliating list of all the ways your brain can deceive you. It’s a wonder our students learn anything!
- Dylan Kane says Don’t Talk to Me About the Factory Model of Education. The discussion continues in Followup: The Factory Model.
- Amy Porter shares Math Resources For Black History Month, but there’s no reason to limit these to February.
- Finally, I launch a new blog series of printable journaling investigations called Morning Coffee: Professional Development for Homeschooling Parents and Other Teachers.
[Puzzle by Play With Your Math blog.]
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Giving Credit Where It’s Due
The puzzles are from Joey Kelly and Xi “CiCi” Yu at PlayWithYourMath.com. Banner photo (top) copyright © AntonMatyukha / Depositphotos.
And that rounds up this edition of the Playful Math Education Blog Carnival. I hope you enjoyed the ride.
The next installment of our carnival will open sometime during the month of March. We don’t have a host signed up yet. Would you like to do it?
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 Education Blog Carnival, please speak up!
Denise Gaskins' Let's Play Math 