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Hello from Natural Math! Send us your questions, comments, and stories of math adventures at moby@moebiusnoodles.com

In this newsletter:
If you live near Cary, NC, join us on Saturday November 8, from 10 AM to noon as we explore the many dimensions of art and nature. This is a great opportunity to connect math to the world around you. We suggest you RSVP for this event by emailing cva@caryvisualart.org
If you don’t live near Cary, but would love to help us organize a math scavenger hunt in your area, drop us a line!
Is it for adults only?
Not at all! Our scavenger hunts are open to all ages. No prior knowledge of specific math concepts is required.
How much does it cost?
The event is free. It is a part of the Year of Sculpture initiative by the Cary Visual Art council.
What will it be like?
Check out this short video from one of our previous Math Treks. (That’s what we call our math scavenger hunts.)
For this Trek, meet us on the green in front of the Cary Arts Center to pick up your Math Trek card. It will have all the clues you need to successfully complete the Trek. Walk around Downtown Cary, enjoy this year’s sculptures, notice beautiful math, and take pictures of your finds. Come back to the green and try our hands-on activities for all ages.
Will I be able to complete the challenges if I am not a math whiz?
Absolutely! There are many answers to each clue and no prior knowledge of math is required. Open-mindedness, creativity, and curiosity rule the day! Check out a few sample clues from this Trek:

Art by Mary Jo Hoffman, Eric Troffkin, and Tom Friedman.
Will there be prizes?
Complete the challenges, e-mail us your photos, and be entered into a drawing to win a copy of our book, Moebius Noodles: Adventurous Math for the Playground Crowd.
How can I volunteer for this event?
We are so happy you’ve asked! You can volunteer at our math craft table or help us lead the tours. Email us at moby@moebiusnoodles.com

Hardly any math symbols were used before the sixteenth century. What did mathematicians rely on for their work before then? And how did mathematical notations evolve into what we know of today? Enlightening Symbols explains the fascinating history behind the development of our current mathematical notation system, shows how symbols were used initially, how one symbol replaced another over time, and how written math was conveyed before and after symbols became widely adopted.
On Wednesday, November 5 at 12pm EST, join us for the open, free online event in the Math Future series. Dr. Joseph Mazur will talk about his new book, Enlightening Symbols. Come and listen to a short presentation, chat with like-minded people in the audience, and ask Joseph questions.
https://naturalmath.com/math-future-event-registration/
As soon as we saw this Thinky the Dragon video, we wanted to make one (or more) of these cuties ourselves. And you can too, by downloading and printing a free template with instructions from ThinkFun. How is this “hollow face” optical illusion mathematical? Watch this video to find out!
You are welcome to share this newsletter online or in print.
Talk to you soon! Dr. Maria Droujkova and Yelena McManaman
Subscribe and read archives
Pinterest | Twitter | Facebook | Google+
Hi, I am Moby and I bring you the news about Natural Math. Send me your questions, comments, and stories of math adventures at moby@moebiusnoodles.com

In this newsletter:
Watch out for a BIG announcement tomorrow!
We’ve been very busy creating something really big and exciting! What is it? It is something many of you asked for over and over – an online course unlike anything we’ve offered before. Usually when you sign up for our courses, you receive plenty of ideas for math games and activities. In this course, you will learn how to create your own activities and how to lead your own math circles (and you will still get lots of ideas for math activities).
We wanted to make sure that everyone who enrolls in this course gets individual attention and support from us, so we limited the 8-week pilot program to 20 participants. We will send a separate e-mail with all the details of the course (including an early-bird registration offer) at 10am EST on Friday, October 17th. Don’t miss it!
Who leads math circles and why?

Anna Ignatov attended a math circle as a child, and then, as a mom, organized two circles for her two daughters and their friends. Since 14, Anna’s daughter Ida has been organizing math circles of her own: the third generation of circles, and counting! Why do they continue this tradition?
As Ida told us:
In school, we are taught that math is something boring, that we have to learn for some strange reason: you will need it in the future. Yeah, sure… It is nice to show the kids the beauty of math before they will learn once and forever that math is boring.
Read the entire interview with Anna and Ida in our 1001 Circles series and try a combinatorics game Anna and Ida shared with us.
Play this cute and easy multiplication puzzle with your kids
The new puzzle game Bojagi by David Radcliffe, which we review on the blog, is all about drawing areas. The rules are easy to learn, but Bojagi puzzles themselves are can be tricky to solve. Draw a rectangle around each number by clicking and dragging with a mouse. Each rectangle should contain exactly one number, and the area of the rectangle should be the same as the number it has. Rectangles must not overlap. That’s it!

Playful and gentle, this puzzle will help your kids see multiplication as more than just repeated addition. Take turns making puzzles for each other. Bojagi interface makes drawing designs, using algebraic formulas, or just playing with shapes easy. An online game, like Bojagi, that you and your child can play together is a great example of a new development in gaming called “intergenerational game design”. It is also one of the guiding principles we use in designing all Natural Math activities.
Speaking of multiplication games, come November we will once again be offering our most popular course, Natural Math Multiplication. We will announce the exact dates and registration details in our next e-mail.
Live open Math Future event: Russian School of Mathematics

On Wednesday, October 22 at 1 PM Eastern Inessa Rifkin, Irina Khavinson, and Nina Dubinsky will talk about the Russian School of Mathematics, one of the largest enrichment programs in the Northeastern US. Come and listen to a short presentation, chat with like-minded people from all over the world, and pose questions for the founders of RSM.
Register to join the event and get notified when we post the recording.
Math Future is an international network of people who care about mathematics education: researchers, developers, teachers, parents, and students. Since 2009, it has organized more than a hundred live online events with leaders of amazing projects.
You are welcome to share this newsletter online or in print.
Talk to you soon! Moby Snoodles, aka Dr. Maria Droujkova
Why would you decide to lead a math circle? Anna Ignatov attended a math circle as a child, and then, as a mom, organized two circles for her two daughters and their friends. Since 14, Anna’s daughter Ida has been organizing math circles of her own: the third generation of circles, and counting! Read Anna and Ida interview to see how their wishes for different mathematics as well as their happy childhood memories of math circles inspired them to organize their own circles.
Ida: When the kids are thinking, they suggest ideas that you would never expect.
In our 1001 Circles series, we feature math circles stories from the point of view of a circle leader, who acts a tour guide. In the companion series 1001 Leaders, we put the spotlight on the leaders themselves. What got them started and what keeps them going? What are their math dreams and worries? If you lead a math circle, an engineering club, or an informal playgroup, we would like to hear your story or interview you. Write moby@moebiusnoodles.com to talk about your adventures.

What brought you to math circles?
Anna: Since the age of 10 I was participating in math activities for kids. When my daughter Ida started school, I was looking for some activities to show her the beauty of math, but I couldn’t find anything that looked nice enough. So I invited Ida’s friends and we started this adventure. Our group kept going for six years, until the kids turned twelve, with five kids participating. Later I organized another group for Ida’s sister and her friends.
The idea was to show that there are not only instructions on “how to do math”, but also a place for thinking. I was also trying to find connections between math we learn at school and our real life.
Ida: When I was 14, I tried to repeat my mom’s experiment. I led a group of six-year-old children under my mother’s supervision. This group met for one year. Later, when I graduated school and started at the university, a boy I babysat since he was born went to school, so I created a group for him.
In school, we are taught that math is something boring, that we have to learn for some strange reason: you will need it in the future. Yeah, sure… It is nice to show the kids the beauty of math before they will learn once and forever that math is boring. Otherwise, their only chance to find out that math is nice is at the university, and only if they choose to study math. Another great thing is to see them thinking and enjoying it.

When the kids are thinking, they suggest ideas that you would never expect. For example, we checked different shapes for symmetry by building them with magnets, or by folding paper. Children came up with their own definition of a symmetric triangle: “Two identical edges, and the third one is even.” A child’s answer might be wrong, but the way of thinking is creative. Children become very happy when they feel that they caught the idea or found the reason for something.
Can our readers try one of your favorite activities from your math circle?
Ida: Once we decided to check how many different “chains” (sequences) of five objects we can make. We had two green stickers and three blue stickers. Everybody made a chain, and then we checked together if we already had that chain or not. Little kids don’t know combinatorics theory, but guess what? We eventually found 10 chains.

After that, we made a “tree” of those chains. You start with the two options, blue or green. Then you build “branches” and reason: to this branch, you can add blue or green, but to this one, you can only add green, because you ran out of blue… We counted the branches, marking them with stickers, and found out that there were – you don’t say – 10 branches! Making chains and making trees were two different activities. We discussed the connections only after we made the tree. Children liked discussing the connections. We didn’t attempt a rigorous proof that we found all the combinations, but we discussed why the tree shows us all of them.

It took us three meetings to explore and model the problem in depth. Children understood that there are 10 and no more chains, and were interested in discussions. We took breaks from the problem when kids got tired, did other activities, and then came back to the problem at the next meeting.
Anna: One very popular activity was “programming the robot.” To start, we decided together what we wanted our robot to do. We used a little doll (“the robot”) and a chess board. At first we just wanted our robot to arrive to the given corner cell, from any other cell. We had cards with commands, like GO, TURN RIGHT, and also conditional questions, like AM I AT THE EDGE? The algorithm was built from these cards. The task for the doll was to arrive from any cell on the board to the corner. One of the kids was looking only at the algorithm, giving orders to the robot and asking questions. All the other kids were moving the robot and answering questions. [This is an incredibly rich math circle task; check out a story in our 1001 Circles series about a similar activity, by DrTechniko – MariaD.]
The activity inspired discussions with kids. For example, they wondered how a robot knew when to stop. Could it see? Maybe it had some kind of a switch that turned the robot off when it touched the edge of the board?
Then we wanted to define some new robot – and one of the kids proposed to create a flight simulator. We never finished it (I wonder why!) – but we had very nice discussions of what it was supposed to do. We talked about maps and scales, and even tried to guide a robot-pilot through the map.
We returned to the robot game during several meetings. The nice thing is, the kids led the activity, bringing their own ideas of what they wanted to do.
Can you tell us about a difficulty you had when you led math circles?
Ida: One of the difficulties I had with the kids was to make them concentrate. Our circles started at 6 PM, we were tired by that time, and it was often very hard for the kids to get into the lesson. So I decided to begin the lessons with something very intriguing, to catch the kids right away. Then we moved on to the calmer main activities.
Anna: We had one our lesson every week. Sometimes we had to reschedule, or a kid missed a meeting. Young kids do not remember much after a week, let alone two. So, there was the feeling that we were not moving anywhere! I started to record what was happening and to post if online for parents. It helped parents to discuss our lessons at home. Kids could not always explain what we were doing. These posts really helped with our progress, because the parents took a more active part in our mathematics.
What advice can you give to newbie circle leaders?
Anna: The visual part of every lesson is very important. For example, it was a nice idea to build the robot algorithm with cards, rather than just saying the commands. We always used some objects to solve logical problems. We used toys for the classic river-crossing problem, “How can we take a wolf, a goat, and a cabbage in one small boat that can only carry one of them?” Without the toys, it was really hard for kids to follow.
Ida: Don’t expect fast results. Be prepared to return to the same idea again and again, from different points of view. Some day children will surprise you!
Multiplication is not just repeated addition, but what is it? From Montessori beads to algebra tiles, many developers claim the array and area models are great for growing children’s conceptual understanding and fluency in multiplication. You can go on scavenger hunts for the area model in tiles and bricks, and draw your own models using graph paper or computers.

The new puzzle game Bojagi by David Radcliffe (@daveinstpaul) is all about drawing areas. Bojagi’s puzzles make you think, but the rules are easy. Draw a rectangle around each number by clicking and dragging with a mouse. Each rectangle should contain exactly one number, and the area of the rectangle should be the number that it contains. Rectangles must not overlap.
As you draw, the game tells you the two dimensions of your shape, for example, 7 x 4. If you break the rules, your shape disappears. The puzzles provide meditative fun for grown-ups and kids alike. The game helps kids learn multiplication in a gentle, playful manner. Making your own puzzles also feels great: you can draw designs, demonstrate algebraic formulas, or simply play with shapes in open-ended ways. A family or a math circle can take turns designing puzzles for one another.
You can find all the puzzles made so far in a big list, and add your own using the puzzle creator. Here are three quick puzzles I made when I first started playing:

Bojagi demonstrates these design principles:
Here is my interview with Bojagi’s creator, David Radcliffe.
Please tell us a bit about yourself.
I am a college math instructor who is changing careers to software development. I graduated from the University of Wisconsin-Milwaukee with a Ph.D. in mathematics. I am interested in finding new ways to use software to help students learn mathematics, especially the tools that encourage exploration and creativity, not just memorization and skill development.
What is the motivation behind your game?
My game presents multiplication in a meaningful context: the area model. I think that it will help students to memorize multiplication facts, but also to understand them visually. It was very important to me that students should be able to create their own levels and share them with their friends, because I want to encourage exploration and play.
Many people say the area model is their favorite model of multiplication. What about you?
The area model is my favorite model of multiplication because it is so easy to visualize. The area model makes many of the properties of multiplication clear, such as the commutative and distributive properties. One weakness of the area model is that it is difficult to interpret multiplication with negative numbers using this model. In that case, I prefer to describe multiplication as scaling.
Your game has a lot of bridges to ideas. Can you name a few?
Besides practicing multiplication facts, the game can be used to explore factorization, divisibility, and prime and composite numbers. A child playing this game can discover that prime numbers can be covered by only one kind of rectangle. Kids may be led to ask which numbers can be covered by two kinds of rectangles. This line of investigation quickly leads to some very interesting concepts in number theory.

(This is a screenshot I took while making a puzzle that can lead someone to explore different ways to factor the same number – MariaD)
Anything else you would like to add, David?
I am a fan of your work with Moebius Noodles, so I am very happy that you are interested in my game. I would be glad to answer any questions that you have. Also, if you have any great ideas for games that I could implement, please pass them along.
Please leave questions and game ideas for David in the comments!