## Morning Coffee – 23 Sept 2019

One of the best ways we can help our children learn mathematics (or anything else) is to always be learning ourselves.

Here are a few stories to read with your Monday morning coffee:

• David Butler invented a challenging new game that can spark plenty of mathematical thinking: Digit Disguises.
• If you liked James Tanton’s video on the area model in last week’s post, you may enjoy his in-depth discussion of The Astounding Power of Area.
• On a lighter note, I’m sure any classroom or homeschool teacher can think of several ways to use Sara VanDerWerf’s collection of Math Fails. Scroll down for links to earlier collections, too.

“I told them that actually what they did was exactly what maths is — reasoning things out using the information you have and being able to be sure of your method and your answer. Just because there’s no symbols, it doesn’t mean it’s not maths.”

—David Butler
The Seven Sticks and what mathematics is

“I am not willing to teach mindless math. It leads to mindless adults. Thinking is not an add-on once they have memorized. Thinking is the basic tool to negotiate the world.”

—Geri Lorway
Teaching division?… Do you know the “basics”?

CREDITS: Feature photo (top) by Kira auf der Heide via Unsplash. “Morning Coffee” post format inspired by Nate Hoffelder at The Digital Reader.

## Morning Coffee – 19 Sept 2019

One of the best ways we can help our children learn math (or anything else) is to always be learning ourselves.

Here are a few stories to read with your Thursday morning coffee:

“Most people think that maths is replete with factual knowledge. But actually, it’s subjects like English, the Humanities, and some sciences that are hefty in factual content. Maths is super-dense with concepts, and processes, but really only very few facts.”

—Kris Boulton
Why Maths Teachers Don’t Like Knowledge Organisers

CREDITS: Feature photo (top) by Kira auf der Heide via Unsplash. “Morning Coffee” post format inspired by Nate Hoffelder at The Digital Reader.

## Morning Coffee – 17 Sept 2019

One of the best ways to help our children learn math (or anything else) is to always be learning ourselves.

Here are a few stories to read with your Tuesday morning coffee:

• David Wees discusses ways to use visual patterns to introduce and extend students’ understanding of algebra and functions.

“What we should all be shooting for is a world where everyone is mathematically literate, and where fear or anxiety around mathematics doesn’t prevent people from doing the things they dream of doing. Everyone should see some beautiful mathematical ideas and know what it feels like.”

CREDITS: Feature photo (top) by Kira auf der Heide via Unsplash. “Morning Coffee” post format inspired by Nate Hoffelder at The Digital Reader.

## Math Makes Sense — Let’s Teach It That Way

I had forgotten this video, and then rediscovered it yesterday and loved it just as much as ever. Perhaps you’ll enjoy it, too — especially if you think of yourself as “not a math person.”

Annie Fetter is talking to classroom teachers, but her message is just as important for homeschoolers. Math is all about making sense. Let’s help our kids see it that way.

You can download the notes for Fetter’s updated session on sense-making and find several links to wonderful, thought-provoking posts on her blog:

### How Can We Encourage Sense-Making?

Here are some ideas from Fetter’s updated notes, which expand on her comments in the video above:

• Get rid of the question. Literally.
• Ask students “What could the question be?”
• Get rid of the question and the numbers.
• Ask “Why?” or “How did you know?” or “How did you decide that?” or “Tell me more about that.”

### A Few Resources to Practice Sense-Making

In no particular order…

“I implore you, stop ‘cracking the math code.’ Make sense-making the focus of every single thing you do in your math classroom.”

—Annie Fetter
Sense Making: It isn’t Just for Literacy Anymore

CREDITS: “Building a rocket ship” photo by Kelly Sikkema via Unsplash. “Reading is thinking” poster by Teacher Trap via Teachers Pay Teachers.

## Playful Math Education Carnival 123: Hundred Chart Edition

Do you enjoy math? I hope so!

If not, browsing this post just may change your mind.

Welcome to the 123rd edition of the Playful Math Education Blog Carnival — a smorgasbord of delectable tidbits of mathy fun.

The Playful Math Carnival is like a free online magazine devoted to learning, teaching, and playing around with math from preschool to high school. This month’s edition features $\left ( 1 + 2 + 3 \right )^{2} = 36 \:$ articles from bloggers all across the internet.

You’re sure to find something that will delight both you and your child.

By tradition, we start the carnival with a puzzle in honor of our 123rd edition. But if you would like to jump straight to our featured blog posts, click here to see the Table of Contents.

Or more, depending on how you count. And on whether I keep finding things to squeeze in under the looming deadline. But if there are more, then there are certainly 36. Right?

## The 1-2-3 Puzzle

Write down any whole number. It can be a single-digit number, or as big as you like.

For example:
64,861,287,124,425,928

Now, count up the number of even digits (including zeros), the number of odd digits, and the total number of digits it contains. Write those numbers down in order, like this:
even 12, odd 5, total 17

Then, string those numbers together to make a new long number, like so:
12,517

Perform the same operation on this new number. Count the even digits, odd digits, and total length:
even 1, odd 4, total 5

And do it again:
145
even 1, odd 2, total 3

If you keep going, will your number always turn into 123?

## Mathematics Is Worthy

“When I began my college education, I still had many doubts about whether I was good enough for mathematics. Then a colleague said the decisive words to me: it is not that I am worthy to occupy myself with mathematics, but rather that mathematics is worthy for one to occupy oneself with.”

Rózsa Péter
Mathematics is beautiful
essay in The Mathematical Intelligencer

### Rózsa Péter and the Curious Students

I would like to win over those who consider mathematics useful, but colourless and dry — a necessary evil…

No other field can offer, to such an extent as mathematics, the joy of discovery, which is perhaps the greatest human joy.

The schoolchildren that I have taught in the past were always attuned to this, and so I have also learned much from them.

It never would have occurred to me, for instance, to talk about the Euclidean Algorithm in a class with twelve-year-old girls, but my students led me to do it.

I would like to recount this lesson.

What we were busy with was that I would name two numbers, and the students would figure out their greatest common divisor. For small numbers this went quickly. Gradually, I named larger and larger numbers so that the students would experience difficulty and would want to have a procedure.

I thought that the procedure would be factorization into primes.

They had still easily figured out the greatest common divisor of 60 and 48: “Twelve!”

But a girl remarked: “Well, that’s just the same as the difference of 60 and 48.”

“That’s a coincidence,” I said and wanted to go on.

But they would not let me go on: “Please name us numbers where it isn’t like that.”

“Fine. 60 and 36 also have 12 as their greatest common divisor, and their difference is 24.”

Another interruption: “Here the difference is twice as big as the greatest common divisor.”

“All right, if this will satisfy all of you, it is in fact no coincidence: the difference of two numbers is always divisible by all their common divisors. And so is their sum.”

Certainly that needed to be stated in full, but having done so, I really did want to move on.

However, I still could not do that.

A girl asked: “Couldn’t they discover a procedure to find the greatest common divisor just from that?”

They certainly could! But that is precisely the basic idea behind the Euclidean Algorithm!

So I abandoned my plan and went the way that my students led me.

— Rózsa Péter
quoted at the MacTutor History of Mathematics Archive

### For Further Exploration

Note: When the video narrator says “Greatest Common Denominator,” he really means “Greatest Common Divisor.”

CREDITS: “Pink toned thoughts on a hike” photo courtesy of Simon Matzinger on Unsplash.