Math(s) Teachers at Play #88 via mathematicsandcoding

From elementary to high school, manipulatives to Minecraft, there’s plenty of fun to be had at this month’s math education blog carnival:


“So, here is issue 88 of the Math(s) Teachers at Play blog carnival. This acts as a round up of some cool blog posts that have been published since issue 87 over at cavmaths. As usual people have submitted entries, which I will supplement with some posts that I have really enjoyed reading in the last few weeks…”

Click here to read the blog carnival post at mathematicsandcoding.

[Feature photo (top) by Pratham Books, 88 cards photo by Bailey Weaver, both via Flickr (CC BY 2.0).]

Noticing Fractions in a Sidewalk


My daughters didn’t want to admit to knowing me, when I stopped to take a picture of the sidewalk along a back street during our trip to Jeju. But aren’t those some wonderful fractions?

What do you see? What do you wonder?

Here is one of the relationships I noticed in the outer ring:

\frac{4 \frac {2}{2}}{20} = \frac {1}{4}


And this one’s a little trickier:

\frac{1 \frac {1}{2}}{12} = \frac {1}{8}

Can you find it in the picture?

Each square of the sidewalk is made from four smaller tiles, about 25 cm square, cut from lava rock. Some of the sidewalk tiles are cut from mostly-smooth rock, some bubbly, and some half-n-half.

I wonder how far we could go before we had to repeat a circle pattern?

Continue reading Noticing Fractions in a Sidewalk

Murphy Strikes My Paperbacks :(

The colors are supposed to go all the way off the edge.
The colors are supposed to go all the way off the edge. They worked just fine in the pre-publication proof…

Murphy’s Law struck today, and the paperback books that looked so good in the proof copies turned out to have a cover glitch, at least in the ones I ordered from Amazon. I’m working with CreateSpace to make sure it gets straightened out—but that means the books may show up as “unavailable” for awhile.

As with any print-on-demand glitch, if you got a badly printed book you can ask Customer Support to replace it.

It could be worse. The interior of the book is fine, at least in my copy. And of course, the ebook versions are totally unaffected.

If you are trying to use the discount code for newsletter subscribers, remember that it’s good through the end of the month. I may even extend the expiration date, if this cover problem persists, but I sure hope to have it fixed in a couple of days.

30% Discount for Email Newsletter Subscribers


[Feature photo (above) by Glen Wright via Flickr (CC BY 2.0).]

Wouldn’t it be wonderful if math was something your children WANTED to do?

With the Math You Can Play series, your kids can practice their math skills by playing games with basic items you already have around the house, such as playing cards and dice.

Paperback editions of the first two Math You Can Play books will be out any day now. If you’re subscribed to my Tabletop Academy Press Updates email newsletter, I’ll be sending you a 30% discount code by Thursday, or as soon as both books pass through the last few publishing hoops…

Playful Math Snacks: Proofs Without Words

sloyd squareThe July “Let’s Play Math” newsletter went out earlier this week to everyone who signed up for Tabletop Academy Press math updates.

Inspired by my recent Infinite Cake post, this month’s issue focuses on math proofs without words. What fun!

Sign Up Today

If you missed this month’s edition, no worries — there will be more playful math snacks coming soon. Click the link below to sign up today!

And remember: Newsletter subscribers are always the first to hear about new books, revisions, and sales or other promotions.

Happy Math Equation Day!

math equation day

Every Day Is Mathematics Day!

I’m still having fun with David Coffey’s meme, which started a couple of years ago with this blog post:

Make Your Own

Would you like to create a math holiday, too? Try one of these sign generators:

What kind of math will you celebrate? Leave a link to your Happy Math Day post in the comments below!

Math Teachers at Play #87 via CavMaths


Puzzles, comics, problem-solving, and mathy conversations with kids‌—‌you’ll find all this and more at the new math education blog carnival. Check it out, click some links, and enjoy!

“Hello, and welcome to the 87th Edition of the monthly blog carnival “Math(s) Teachers at Play”. For those of you unaware, a blog carnival is a periodic post that travels from blog to blog. They take the form of a compilation post and contain links to current and recent posts on a similar topic. This is one of two English language blog carnivals around mathematics…

This month has been fairly busy in the way of maths blogs and we have a treat for you, so to start the carnival here are the submissions we received…”

Click here to go read Math(s) Teachers at Play 87.

Infinite Cake: Don Cohen’s Infinite Series for Kids

Math Concepts: division as equal sharing, naming fractions, adding fractions, infinitesimals, iteration, limits
Prerequisite: able to identify fractions as part of a whole

This is how I tell the story:

  • We have a cake to share, just the two of us. It’s not TOO big a cake, ‘cuz we don’t want to get sick. An 8 × 8 or 16 × 16 square on the graph paper should be just right. Can you cut the cake so we each get a fair share? Color in your part.

Bobby Flay German Chocolate Cake

  • How big is your piece compared to the whole, original cake?
  • But you know, I’m on a diet, and I just don’t think I can eat my whole piece. Half the cake is too much for me. Is it okay if I share my piece with you? How can we divide it evenly, so we each get a fair share? How big is your new piece? Color it in.
  • How much of the whole, original cake do you have now? How can you tell?
  • I keep thinking of my diet, and I really don’t want all my piece of cake. It looks good, but it’s still just a bit too big for me. Will you take half of it? How big is that piece?
  • Now how much of the whole, original cake do you have? How could we figure it out?
    [Teaching tip: Don’t make kids do the calculation on paper. In the early stages, they can visualize and count up the fourths or maybe the eighths. As the pieces get smaller, the easiest way to find the sum is what Cohen does in the video below‌—‌identify how much of the cake is left out.]
  • Even for being on a diet, I still don’t feel very hungry…

Continue reading Infinite Cake: Don Cohen’s Infinite Series for Kids