### What’s Special about 140?

Ladies and Gentlemen, welcome to the 140th Playful Math Education Blog Carnival! Feast your eyes on the number, 140, the 7th member of the famous Square Pyramidal Number family. Watch as 140 performs these amazing feats:

140 is the 7th square pyramidal number because

(7³/3) +(7²/2) + (7/6) = 140.

140 has twelve factors and will now use them to make a lovely factor rainbow:

For140’s next trick, see what happens when it is divided by six of its non-factors:

Finally, 140 is the fourth harmonic divisor number, and Wolfram Math World even uses 140 to explain what a harmonic divisor number is.

Now let’s move on to the blog entries for this month’s carnival:

### Children’s Literature and Math

Kelly Darke of Math Book Magic wrote a post about a brand new entry in children’s literature, The Boy Who Dreamed of Infinity. This is the story of the great Indian mathematician, Ramanujan. The book is available for us to read now, but Kelly was able to read it for the first time last year. I felt so much joy inside of me as I read first her reaction to the description of the book and later to the book itself. I am grateful that the mere idea of that book prompted Kelly to create a blog to share the magic of good mathematical children’s literature.

Rhapsody in Books Weblog tells us about, Raye Montague, an African-American girl born in 1935. She was told repeatedly that her race and her gender would prevent her from becoming the mathematician that she dreamed of becoming. She didn’t heed her naysayers. The Girl with a Mind for Math: The Story of Raye Montague tells her inspiring story.

On world Tessellation Day, *TheKittyCats *blog introduced us to Tessellations! Children will enjoy looking at the illustrations in the book and won’t even realize they are learning some math in the process unless someone shares that secret.

### Games and Math

Alan Parr of Established 1962 explains how to play Dotty Six, a game played with a tic tac toe grid and a die. Because he asked himself, “What If Not?”, he was able to suggest some mathematically interesting variations of the game as well.

Mrs. O’Brien started her blog, Math Epiphany, very recently-in May 2020. She has written two posts about using games to learn mathematics. She writes about card games in Summer Math Fun: Math Games, and about board games in Summer Math Fun: Good Old Fashioned Games.

Denise Gaskins shares a math game that lets children complexify expressions or equations rather than simplify them. Making the expression or equation a little more complex than it was before can be great fun and wonderfully educational. Check out The Best Math Game Ever!

Do you know how to play Dara, Five Field Kono, Mu Torere, Pong Hau K’I, Shisima, or Triangle Peg Solitaire? I’ve never even heard of these games before. Mark Chubb of Thinking Mathematically introduces all of these games in Math Games-building a foundation for mathematical reasoning. One of the games is illustrated in the tweet below.

I have some math games (K-adult) for you to play at school, through distance learning, or with your families.

Take a look:https://t.co/2eoRRVegTE#mtbos #iteachmath #elemmathchat #msmath #distancelearning #BackToSchool— Mark Chubb (@MarkChubb3) August 22, 2020

### Math and Paper-Folding

How is making a pouch out of a newspaper doing math? Paula Krieg and John Golden explain that it can be more than simply taking measurements and using rulers in Pouch: Something from Almost Nothing #3.

Did you know that paper folding can help kids understand systems of linear equations?

I’ve taught Algebra students about Systems of Linear Equations for years. I’m also a big fan of paper folding.

I recently had an “ah-ha moment” when I realized that these two things are closely connected.

Thanks to @PaulaKrieg for her support!https://t.co/1XYJe4uKkJ

— Mark Kaercher (@shskaercher) August 14, 2020

Or paper folding can even help kids understand Knot Theory or Topology?

Paper folding square trefoil knot, inspired by @panlepan and @motoyaman6 ‘s recent tweets. #matharthttps://t.co/lGhKrSTvwJhttps://t.co/6KbOnD92Ku pic.twitter.com/Ycbk4bh3lJ

— Kukan Kogei (@asahidari) August 26, 2020

### Math and Art

What creatures can be seen in these numbers? Click on the video to find out what one artist saw!

— Painting & Arts 🎨 (@ArtsDoing) August 25, 2020

We can always count on Robert Loves Pi to create dazzling and beautiful geometric art. Here he tells us how relaxing it is to produce it:

#Tessellation Featuring Circles and Rhombi https://t.co/YLXeOy62TN

— RobertLovesPi (@RobertLovesPi) August 23, 2020

Photographer Ming Thein shares 13 discussion-evoking photos in Photo essay: The texture of geometry. I’d love to hear some of those discussions!

Quilts can be stunning examples of mathematical art. Aby Dolinger of Abyquilts has created a quilt pattern she calls “Math Whiz,” and this mathy quilt was featured on the July/August 2020 COVER of Quiltmaker magazine! Congratulations Aby!

### Geometry and Trigonometry

Laura of Mathsux² has written an explanation and created a video to take the mystery out of trigonometric ratios in How to Use SOHCAHTOA.

Jo Morgan’s website is filled with resources to make teaching and learning math more effective, and yet she always finds room for more ideas! She recently created her 133rd Maths Gems Post that included some playful ways to look at angles in a circle and areas of rectangles inside of a larger rectangle. . . Now to segway into word problems. . . If Jo writes two Maths Gems a month and her July 30th post was number 133, and the Playful Math Blog Carnival comes out ten times a year and this is the 140th post, when will the Maths Gems number and the Playful Math Blog number be the same number?

### Word Problems

I love the giant Sequoia Trees. This blog post has story problem suggestions about Sequoia Trees for every age group:

Branch out and up up up with astounding #sequoia trees in today’s #bedtimemath! https://t.co/YVJeRq1iE9 #MathInNature #ParentsCount pic.twitter.com/aK5l1U0RU7

— Bedtime Math (@BedtimeMath) August 25, 2020

A-Hundred-Years-Ago Blog explores some Hundred-year-old Food-related Math Problems when large oranges were only 60 cents a dozen. Go back in time and enjoy solving these with your students! Let them compare them with word problems from the 21st century.

### Puzzles

Here are some small puzzles based around divisibility, with arrows revealing which number divides which. Dots indicate that neither divides the other.

For solutions, PDFs, other versions, and more info visit: https://t.co/zICZEDu8L1 #mtbos #Puzzle #puzzles #math #maths pic.twitter.com/YdDoEKpErA

— David Nacin (@quadratablog) August 26, 2020

Alan Paar of established1962 shares his last experience helping kids play with math before the lockdown. It was a series of puzzles that made A Lesson That Will Stay With Me. He has used these adventures for 30 years and kids enjoy them so much. He was especially glad that these puzzle adventures will be their last memories of attending primary school. They was so much better than Key Stage 2 SATs.

The Find the Factors puzzles I create are a playful way to get to know the multiplication table better. This level 3 puzzle can be solved by considering the factors of 30 and 90 where only factor pairs with numbers from 1 to 10 are used. After those factors are found, write them in the appropriate cells then work your way down the puzzle row by row using logic until all of the factors are found.

Singapore Maths Tuition shares an “average” math puzzle with a twist that might baffle all but those kids who enjoy math but find little challenge in traditional math work. No worries for the rest of us; a good explanation is also included.

### Mathematical Humor

Emily’s Post tells a timely math joke about three ducks that will teach while it delights children in Modern Math.

Joseph Nebus has a humor blog in which he wrote a humorous post he titled What your Favorite Polygon Says about You. I’m not sure what my favorite polygon is, but I will carefully consider all the possibilities.

The Bored Side of the Phone shares a couple of stand-up-comedy-worthy jokes about Mathematics in The Truth About Maths.

### Numbers

Natural Numbers:

Excellent, informed @tes piece from @NumCog

“when children tend to hit Year 1, they are usually expected to be able to use numerical symbols for basic arithmetic when, for some children, they might not be at that point yet.” >> https://t.co/FwMIupazHb— Dr Helen J Williams 🇪🇺#rightfromthestart (@helenjwc) August 5, 2020

The counting numbers/whole number set has been further categorized! Can you imagine how? Read all about it in Publications de BOULAY’s New Whole Numbers classification. As you learned about the set of ultimate numbers, how well did your imagination serve you?

Rational and Irrational Numbers: Mike of Mike’s Math Page gives us a front-row seat observing how he teaches his sons about mathematics in Sharing John Urschel’s great video on rational and irrational numbers with my son.

Imaginary Numbers: Every year Joseph Nebus lets his readers chose mathematical topics for each letter of the alphabet, and then he writes a post about each of those A to Z topics. For 2020 he wrote a serious essay on imaginary numbers that playfully included some comics about some numbers that you can imagine.

### Life skills and Math

Ladybugs or ladybirds want to teach you some math concepts. Come out in the garden with the lesson plans provided by DogwoodDays in Garden Schooling: Ladybird Maths and see what you learn!

Cooking is an important life skill and a fun way to learn about fractions and other math concepts. The For-Health blog featured a post kids and adults can enjoy together: How to Cut Down Recipes: What’s Half of ½ cup, ¾ cup, 2/3 cup and More. Verifying the given measurement equivalents can be great fun for kids so do let that happen!

How can we make our lives be as well-balanced as an equation? That’s a good question for high school students to consider. A life coach’s advice on how to find success in life is given using mathematical symbols and vocabulary in Mathematics of Life, Learn from Math symbols.

### Corona Virus Math

Happy Friday Friends! Got my math mask and my @NCTM math t-shirt. #iteachmath pic.twitter.com/xMQuQFcRp0

— Joanne Philhower (@DrJoJoMath) August 21, 2020

In Wheel of Theodorus – Distance Learning Edition, MrJoyce180’s shares his students’ work creating their own, and I do mean their own, Wheels of Theodorus. All of this creating occurred virtually during the lockdown. He shares both the successes and the failures. This was one of my favorite discoveries while I created this carnival.

*I didn’t have my glasses on* questions Cosco’s mathematical reasoning of cake buying and serving in Let (a few of) them eat cake! Can you formulate a word problem from this post?

### Statistics

When Disney produces a direct to video sequel, will a Roman numeral, an Arabic numeral, or neither most likely appear in the title? Even young children will be able to explore that topic with Joseph Nebus in this Statistics Saturday Post.

World Affairs uses cleverly represented graphs to help us understand The Math of How China Surpasses USA in 5 Years. Understanding the math behind the graphs could help us improve our situation.

### Poetry and Math

How beautiful circles in love can be

Holding together hand in hand

Hiding the triangles their good old friends

A face like a cathedral stained glass

Yellow and green, like jewels from a palace.

🥨✨🥨✨🥨✨🥨✨🥨✨@PerHenrikChris1 https://t.co/FCVEkwvxGw— Belladonna (@christi99830943) August 25, 2020

Beginning with irrational numbers, Prerna’s Blog uses mathematical and poetic language to describe the Mathematics of My Mind.

Math+Life connects math with life by writing poetry. After you read Set in Stone the mathematics of sets is explained followed by how they relate to life. Do we place limits on children or adults when we categorize them into sets of different types of people?

### Making Math More Inclusive

Please read Sunil Singh’s powerful and thought-provoking post, How to Begin Bringing Rich and Inclusive Math History Resources Inside K to 12 Classrooms.

I am also pleased to introduce you to the brand-new BlackWomenRockMath Blog. Their first post is The Brilliance Hiding in Plain Sight in which three women share their sobering math stories. Thankfully, they each were able to overcome negative early experiences in learning mathematics to make worthwhile contributions to mathematics education today.

### Mathematics Carnivals and Amusements:

Every Monday Denise Gaskins invites you over for a Morning Coffee. There she will direct you to other mathematics blogs for your edification and amusement.

There is also a Carnival of Mathematics that may interest you. The current (184th) Carnival is hosted at Tom Rocks Maths.

I really liked putting this month’s carnival together, and I hope you have enjoyed reading it as well. Feel free to stop by and hang out whenever you’d like.

The previous Playful Math Education Blog Carnival #139 was hosted by Math Mama Writes. Be sure to check it out if you haven’t already.

I am already looking forward to the next Playful Math Education Blog Carnival which will be hosted by Joseph Nebus of Nebus Research.

Perhaps you would like to volunteer to host one of the carnivals? Contact Denise Gaskins to get on the carnival calendar! I can’t wait to see what you put together!