Friday, September 25, 2026

Playful Math Blog Carnival 186: Math Stories



… wherein I gather interesting math posts for your reading pleasure, especially those related to math storytelling. 

 

September 25 (today!) is Math Storytelling Day. And starting this year, it seems to also be 9-to-5 Day in honor of Dolly Parton. She might be a patron saint of stories, and I can sure imagine her delighting in math stories. As always, you can celebrate in many ways: read a math story, write your own math story, or support math stories for all.

In my carnival post from a year ago, Playful Math 182, I listed over a dozen of my favorite math stories, said a bit about the history of both Math Storytelling Day and math told in stories, and wrote a silly little math story. I am still working on my favorite math story ever, Althea and the Mysteries of Calculus. It still needs to be fully edited and illustrated before it gets published. But it’s already quite lovely. If you’d like to be a beta reader, you’d be helping me discover what parts of it different people like, and what doesn’t work quite as well as the rest. Contact me at altheasmathmysteries@gmail.com if interested.

 

The stories gathered here come mostly through Denise, and I want to give her credit. I've written this up, but she is feeling the pulse of the math lovers online. Here's one of her early posts on Math Storytelling Day, from 13 years ago. (Some of the links still work...)



186 has some stories to tell! 

We like sharing the stories of the carnival number. 186 has better stories to tell* than many numbers:


  • 186 is a 'prime-additive number' since it can be written as a sum of powers of its prime factors: 2, 3, and 31. Can you find the powers? 
  • It’s also a palindrome in four different number bases. Can you find them? 
  • Have you heard of the four 4s puzzle? Make each number from 1 to 100 using exactly four 4s and any math operations you please. (No other digits allowed.) I’ve worked on that many times over the years. I’ve never tried to go past 100. It turns out that 186 can be found in this way. Can you find it? 
  • See Ken Fan's contribution below! 

  

 

Games & Puzzles

Games are not stories (unless the game is something like Dungeons and Dragons, do you know any mathy story-games?), but games can bring joy to math in their own way. (Why do stories bring joy to math? Why do games bring joy to math? Do they infuse the math with its own joy?)

The Substitution Game, by Sonya Post is a story about a game, and about how children learn to think mathematically.

 

Here's a puzzle so ancient, Archimedes popularized it. Most people just tried to put the pieces together into a rectangle. For him, the interesting question was: How many solutions are there? The Ostomachion is beautiful and complex. Denise has made it accessible for you. And Sarah has written a delightful physics story about it, Allora and the Puzzles of Archimedes. (And we know how close math and physics are, but maybe that's another story.)

 

 

Pat Bellew tells the story of the Towers of Hanoi puzzle, played with 3 posts and disks of varying sizes. The disks start on one post, biggest at the bottom, getting smaller as you go up. They must be moved to another post, with a bigger disk never being above a smaller disk. 

 

Erica gives us Games to go with Stories, where both are from cultures around the world.

 

Fawn Nguyen's Visual Pattern puzzles have moved to a new online home, where they'll be easier to maintain. 

 

 

Stories


This story made me cackle multiple times. It was hard to get my head around the title, Maths Sheep Play Sheep, but the story was pure joy, both hearing David read it, and his longer story of where the words and the sheep came from.





  

I love Denise Gaskins' Alexandria Jones stories. They are full of adventure, and weave in all sorts of mathematical thinking. I hope someday she'll make a book of them. For now, she's reposting the stories one at a time.  Here's The Secret of the Pharaoh's Treasure, along with its sequel, Part 2.

 

John and Xavi Golden (father and son) have collaborated on a graphic novel, AL, Logical (pre-order it here). In this post he explains why a graphic novel was just right for the story he and Xavi wanted to tell.

John Golden also wrote a little story in honor of Math Storytelling Day, Sum Number Party. If you like zines, print this version out and fold it up. (How cool is that?!)   


 

 

A poem and a picture tell a story that makes a proof of the Pythagorean Theorem.** I definitely needed Greg Ross' help to follow that story.

 

 

Learning Math (Stories Included)

Bill McCallum points out that the stories we tell ourselves from math education research are often oversimplified.

 

Physics and math are close companions. Sarah writes stories about physics. Here she writes about the research supporting using stories to teach science.

 

In the Girls' Angle program, Ken Fan sets girls free to explore the math that they find most intriguing. Some of the students have gone on to amazing accomplishments. Milena Harned and Iris Liebman made a mathematical conjecture about the shapes made by crossing lines, and proved it while still in high school. Their paper, which they first submitted in 2022 was finally published just this year, as "An Unexpected Class of 5+-gon-free Line Patterns", in La Matematica, the Journal of the Association for Women in Mathematics.


To go with this blog carnival, Ken created the illustration you see here using 186 lines.  Iris and Milena proved that every polygon formed by those lines is either a triangle or a quadrilateral...no polygons with more than 4 sides!

 

 

And that's it for my birthday carnival! Read the old carnivals here. 

____

*These facts about 186 come from https://www.numbersaplenty.com/186, which I desperately hope isn't part of the AI takeover of the internet. But how can one tell? I rejected at least two possible contributions for this post, suspecting they were AI.

** Calling this theorem the Pythagorean Theorem is Eurocentric. It was proved long before Pythagoras came around. I call it the Right Triangle Theorem. 

Friday, September 18, 2026

Request for Submissions for Playful Math Carnival 186: Math Stories

Calling all math lovers. I'm hosting the fall edition of Playful Math Carnival 186. The theme is once again Math Stories.
 
Have you written a math story?
Have you written an article about stories and math?
Do you have a favorite math story?
Would you like to write something in the next 2 or 3 days, and post it somewhere?
 
I'll be posting this next week Friday, September 25, so I have one week to get the goods and weave them together. September 25 is National Math Storytelling Day. 
 
9-25 is also headed towards being 9-to-5 day in honer of Dolly Parton. She sure loved spreading the joy of stories, and I can certainly imagine her delight at the idea of math stories. I'm so happy to be sharing our math story day with the fabulous Dolly Parton.
 
Got a link? Please send it today

Saturday, August 22, 2026

Limit Definition for Derivatives

Calculus courses usually start with limits, and the precise definition of a limit is usually included but barely. There are a number of problems with this.

First off, limits seem alien and "why are we doing this"? It would be better to start with the derivative, connect it to slopes and velocities, and tell a bit of the history (Newton attempting to understand gravity). Perhaps do some hand-waving about the limits, and promise to come back to them.

The second big problem is that the limit definition is never connected with the derivative definition. In fact, the f(x) in the limit definition is not the same function as the f(x) in the derivative definition. After almost 30 years of teaching calculus, I finally wrote something to explain how the two definitions interact. (I found nothing online about this, and I have never seen it in a textbook.)

I've written it up two ways. One is a bonus chapter for my (not-yet-published) book, Althea and the Mysteries of Calculus, in which there is discussion among the kids and 'Mom'. The other leaves out the characters: How the Definitions of Limit and Derivative Interact

 

Friday, July 24, 2026

Math is the Plot

But a plot usually has a conflict. What's the conflict? (I don't know yet.) And there should be some drama, etc.

I'm now in a critique group for people writing STEM fiction. I recommended Math Girls to one of my critique partners. She mentioned how much she loves trying to solve the problems before the characters do. Duh! I figured something like that would be easy to include in Althea and the Mysteries of Calculus. It took me a few days. Now there's a teaser at the end of each chapter. And the list of those questions makes a great outline for a calculus course.

I'm still working on the characters' responses to those questions. I've already rewritten a number of scenes in exciting ways. Sofia is a very visual thinker, and she often finds answers in very different ways from how Mom would explain.  

 

Check it out.

  

  1. How can we define tangent lines? (p31)
  2. How is it possible to figure out a speed when no time has passed? (p53)
  3. To find instantaneous velocity we need two points infinitely close together. How can we do that? (p62)
  4.  ... 

 

Saturday, June 6, 2026

Book Progress


 

I'm working on removing anything unnecessary from Althea and the Mysteries of Calculus. So far I've only removed 15 pages. At that rate, it would take me a year and a half to get it down to 350 pages. I'd better pick up the pace.

I'm also improving things that beta readers have asked me to. The characters need to move around a little more, and have little physical quirks. I'm working on that. D suggested that one of the characters might chew on their pencil when thinking, and then their pencil would bump into their mask. I like that image. I haven't found a spot yet where it will work, but I hope to.

Someone just asked to read the first book. I wondered what made him ask just now, since I haven't recently asked for readers. I realized maybe it's that school has ended.

 

If your school year has recently ended and you or your kids would like to read one of Althea's Math Mysteries, just get in touch at altheasmathmysteries@gmail.com. I'm still in need of beta readers.

 

More information about the books here. 

 

Wednesday, April 22, 2026

What is calculus?

It finds slopes on curves,

And areas inside curvy shapes.

So it can find a changing velocity,

Like with gravity.

 

How does it work?

We use two points to find slope of a line, rise over run.

But we want the slope of a curve at one point.

So Newton and Leibniz “cheated”,

Putting the two points infinitely close together.

It works.

 

If you want to learn more,

Althea and her friends are exploring calculus

And you can join them.

 

 

(Email me at altheasmathmysteries@gmail.com.) 

Tuesday, February 10, 2026

Progress: Althea and the Mysteries of Calculus, version 8.2

 



Minor changes

The front image is much nicer now. It's still not a professional illustration. That will happen after we begin our kickstarter campaign, and that won't be for many months, at the earliest.

I decided the predictability of having Althea's Math Journal after every chapter would feel good to readers. But the first two Mondays had two chapters each, and she can't be writing her journal in the middle of a gathering. So I had to combine chapters 1 & 2 and also chapters 5 & 6. Done.

Also, at 450 pages, the book is way too long. I intend to shave off at least 100 pages. I found some bits in chapter 1 that could go. (Some of that appears in the Activity Book still.) So that chapter is a reasonable length, I think. So far, I haven't found anything to take out in what is now chapter 4. I hope folks giving me feedback can help me with that. I think it comes in too long at 26 pages.

I'm still finding places where I need to add a bit to make the math clearer. But more and more, I'm also finding bits that can go. Adding a touch of color here, removing something out of place there. I feel like a sculptor or painter. Ahh.

I wish it were easier to find beta readers. (I have a story to tell about that. It will be in a blog post soon.) If you're interested, email me at altheasmathmysteries@gmail.com.

 

 

Table of Contents 

Here it is. Does it entice you?

Prologue                                                                      

Part 1. Slopes on Curves and Changing Velocities

Ch. 1.   Areas and Graphs                                        

Ch. 2.   On Our Own                                                 

Ch. 3.   Working On Our Icons                                

Ch. 4.   Velocity, Acceleration, and Tangents           

Ch.5.    Finally, the Derivative                                 

Ch.6.    Measuring Speed                                          

Ch.7.    Derivatives from Graphs                              

Ch.8.    Even More Perspectives                             

Ch.9.    Finishing Up and a Test                             

 

 

Part 2. So Many Derivatives

Ch.10.  All the Powers                                             

Ch.11.  Polynomials and Graphing                          

Ch.12.  Graphing with Newton                                

Ch.13.  Back to Trigonometry                                  

Ch.14.  Derivatives for Sine and Cosine                  

Ch.15.  Quotients and More Trig Derivatives          

Ch.16.  Optimizing                                                    

Ch.17.  Nested Functions                                          

Ch.18.  Exponential Functions                                  

Ch.19.  Exponential Derivatives                                

Ch.20.  Implicit Derivatives                                       

Ch.21.  Linearization                                                 

Ch.22.  Review and Another Test                              

 


Part 3. Anti-derivatives, Areas, and Volumes

Ch23    Areas                                                            

Ch24    Getting Closer to Area                                 

Ch25    That Area Definition                                   

Ch26    Fundamental Project                                    

Ch27    Gravity                                                         

Ch28    Substitution                                                  

Ch29    Volumes of Revolution                                

Ch30    A Final Exam                                               

Ch31    Back to Infinity                                            

Ch32    Infinite Series                                               

Ch33    Infinite Series for Area                                

 

Epilogue.                                                                  

 

 

 

 

 

 
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