## Posts tagged ‘math’

### Talking Math and Coronavirus With Your Kids #tmwyk

Nothing like a global pandemic to spark a good math conversation.

If you’re a parent from Alabama, Florida, Illinois, Kentucky, Louisiana, Maryland, Michigan, New Mexico, North Carolina, Ohio, Oregon, Pennsylvania, Rhode Island, South Dakota, Virginia, Washington, West Virginia, and Wisconsin — and by the time this post is published, probably many other states — then you’ve got several weeks of quality time with your kids ahead of you. You may be wondering what you can do to fill their time in meaningful and productive ways. Well, my recommendation is to **talk math any time you’re with your kids**, but while COVID-19 is in the news, that suggestion may be more important than ever.

It won’t be long before you tire of questions from your kids about why they have to spend the next two to four weeks at home, about why you won’t let them go to the mall, about why their friends can’t come over, about why they shouldn’t play tag or duck, duck, goose. But don’t get frustrated by their questions. That curiosity is an opportunity to talk about the math of the pandemic while reinforcing the reasons for staying home.

The spread of any disease is dependent on four factors:

- the population of opportunity;
- the number of days an infected person remains contagious;
- the number of people with whom an infected person comes in close contact; and,
- the likelihood of contraction when close contact occurs.

Simulations based on these four factors can be conducted with the **NCTM Pandemics** app (which, unfortunately, requires Flash). The page on which that app resides talks about swine flu, because the app was developed in 2006. But the lessons to be learned from the app are as relevant today — maybe even moreso — as they were 14 years ago.

You can explore on your own, or you can watch the screencast below to see how the spread of coronavirus can be controlled if we all do our part to limit close contact with others.

With your kids, research and discuss appropriate numbers for each factor.

- For display purposes, the app limits the “population of opportunity” to 400. This number falls significantly short of the nearly 8 billion people worldwide who might be infected with coronavirus, but it’s enough to make a point.
- The number of days an infected person remains contagious is unknown, but healthline says that “people who have the virus are most contagious when they’re showing symptoms” and the infection starts with mild symptoms that “gradually get worse over a few days.” It’s reasonable to estimate that an infected person might be contagious for three to five days.
- The number of contacts is
**the only factor**over which we have control. If you go to work or a shopping center, you may have contact with 20 people a day; if your child goes to school, she may interact with 50 other students. But if you follow CDC guidelines, stay home from work or school, and avoid public gatherings, you can reduce the number of contacts to just a handful. - Finally, the chance of contraction is unknown. What is known is that an infected person is likely to transmit COVID-19 to between 2.0 and 2.5 other people if some type of quarantine does not occur. The corresponding chance of contraction would be in the range of 2-4%.

To convince your kids that staying home is a good idea, run the simulation with a large number of contacts. Even if the number of days contagious and chance of contraction are low, **most of the population will become infected if the number of contacts is high**. But then reduce the number of contacts and run the simulation again. **As the number of contacts decreases, so, too, will the percent of the population that gets infected as well as the number of days before the pandemic burns itself out. **

Of note, most of the population will be infected if the days contagious and chance of contraction are both high, regardless of the number of contacts. For instance, if days contagious and chance of contraction are both set to 10, then more than 80% of the population will be infected in the vast majority of simulations, even if the number of contacts is set to 2. However, there are very few diseases for which a person remains contagious for 10 days and the chance of contraction is 10%; and, those numbers are certainly higher than the data would suggest for COVID-19.

### Chuck Norris Math (and Some Science) Jokes

My sons, of course, know that 73 is the Chuck Norris of numbers:

But it hadn’t occurred to me until recently that they had no idea who *Chuck Norris* is. Explaining who he is — that is, trotting out his resume and discussing *Lone Wolf McQuade* and *Walker, Texas Ranger* — is easy enough. But impressing upon them why he’s a bad ass who deserves his own meme? Well, that’s a bit tougher.

But it doesn’t matter. Chuck Norris jokes are just plain funny, even if you have no idea who he is. They’re a genre unto themselves, and the inventor of Chuck Norris jokes deserves as much credit as the inventors of knock knock jokes, one-liners, non-sequiturs, and light bulb jokes.

And I know you’re gonna find this surprising, but of all the Chuck Norris jokes on the internet, my sons most appreciate those involving math. So I present a collection of Chuck Norris math jokes, pulled from various corners of cyberspace, and I hope you enjoy them as much as Alex, Eli, and I do.

Chuck Norris can divide by zero.

Chuck Norris counted to infinity… twice.

The easiest way to determine Chuck Norris’ age is to cut him in half and count the rings.

Using only compass and straightedge, Chuck Norris once trisected an angle and squared a circle simultaneously, one with each hand.

When chuck Norris does division, there are no remainders.

A roundhouse kick from Chuck Norris is faster than the speed of light. This means that if you flip a light switch, you’ll be dead before the light turns on.

Chuck Norris’s body temperature is 98.6 degrees… Celsius.

Chuck Norris can win a game of Connect Four in only three moves.

Chuck Norris can solve a system of equations involving parallel lines.

Chuck Norris can recite the digits of π… *backwards*.

Chuck Norris knows the biggest prime number.

Chuck Norris has every real number tattooed on his forearm.

Chuck Norris doesn’t do mathematics. Chuck Norris *is* mathematics.

Chuck Norris will decide if *P* = *NP*.

If a barber in a village shaves all men who do not shave themselves, then who shaves the barber? Chuck Norris does. Well, sorta. He gives the barber a roundhouse kick and knocks all the hairs from the barber’s face, proving that set theory is both consistent and complete.

Chuck Morris constructed a proof of Fermat’s Last Theorem that would fit within the margin.

If you type 5,318,008 into a calculator and turn it upside down, it’ll spell BOOBIES. If Chuck Norris turns a slide rule upside down, it’ll be so scared that it’ll spell anything Chuck Norris wants it to.

Chuck Norris doesn’t do linear programming; for him, there are never any constraints.

Chuck Norris doesn’t avoid calculation mistakes. Calculation mistakes avoid Chuck Norris.

Chuck Norris can cross a vector with a scalar.

Chuck Norris destroyed the periodic table, because he only recognizes the element of surprise.

Why is 6 afraid of Chuck Norris? Because Chuck Norris 8 9.

### A No-Op KenKen for Today

This will be a short post, just to share a puzzle for today.

There’s nothing inherently special about today — though it is the 30th anniversary of The Simpsons airing on Fox, and, slightly less important, the anniversary of Wilbur and Orville Wright’s famous flight — except that (a) I introduced the students in our middle school math club to KenKen last week, and (b) today is our last meeting before the holiday break, so I thought I’d do something special and create a KenKen puzzle that used the numbers from today’s date. I had hoped to include 12, 17, 20, and 19 as the target numbers in the cages, but that effort proved fruitless. Instead, I opted for 12, 1, 7, and 19 as the target numbers, and I filled in the single-cell cage in the bottom right with its number, 3.

I rather like the result. The puzzle is not terribly difficult; and, the solution is not unique, which I figure is perfect for kids who just learned about KenKen a week ago.

If you’re not familiar with No-Op KenKen, they’re just like regular KenKen puzzles, but the operation isn’t included with the target number. Instead, you’ll need to discern the operation for each cell. (For another example of a no-op KenKen puzzle, check out Harold Reiter’s No-Op 12 Puzzle.)

Enjoy, good luck, and happy December 17!

### It’s Been Too Long

I can’t help but channel my inner Foo Fighter as I start this post.

This is a call to all my past resignations;

It’s been too long…

Too long, indeed. My last post was August 8. I’ll use starting a new job and moving my family across the country as my excuse, but you deserve better. To get back into the swing of things, and to try to earn back your trust, I’ll start with a listicle of sorts. Let’s call it **12 Math Jokes You Should’ve Heard By Now**. (Think that’s enough click-bait to get this post a thousand likes? We’ll see.)

—

Knock, knock.

Who’s there?

Pi.

Pi, who?

Don’t listen to me. I’m irrational.

I picked up a hitchhiker, and he seemed like a good guy. We had a pleasant conversation for a few minutes, and then he asked, “Thanks for picking me up. But weren’t you afraid I might be a serial killer?”

“Nah,” I said. “The odds of two serial killers in one car is extremely unlikely.”

I had a calculus test this morning. I thought about praying for a good grade. But I know God doesn’t work that way. So instead, I copied off my classmate who’s been accepted to Harvard, and I prayed for forgiveness.

I asked my wife, “What would you do if I won the lottery?” She said she’d take half and leave me. “Great!” I said. “I just won $10. Here’s $5. Don’t forget to write.”

Why did the math student ask a chemist for help?

He heard chemists have a lot of solutions.

Why was the fraction skeptical about marrying the decimal?

Because one of them would have to convert.

Atheists have difficulty with exponents because they don’t believe in higher powers.

The nurse apologized after realizing he’d put the splint on the patient’s incorrect finger. “You were really close,” said the patient. “You were only off by one digit.”

How is *x*^{2} + 2*x* + 4 = 0 like an artificial holiday tree?

Neither have real roots.

At a job interview, tell them you’re willing to give 110%. Unless you’re interviewing to be a statistician.

My girlfriend is like the square root of -100. She’s a perfect 10, but purely imaginary.

My wife calls me

, because I’m never right.obtuse triangle

### Ch-Ch-Ch-Changes — in Job and Location

**A few days back**, I mentioned that I had a new job and had moved across the country, and I said I’d write more about that later. Well, it’s later.

After six wonderful years of developing a highly-rated, award-winning, interactive math textbook at Discovery Education, I’ve taken a new position at the **Math Learning Center**, a non-profit organization in Portland, Oregon. The Math Learning Center (MLC) is the publisher of *Bridges*, an award-winning elementary math curriculum.

The reason for the change? Well, actually, there are several…

- MLC is not-for-profit, so any money raised from curriculum sales is used to improve the materials and professional development offerings.
- The mission of the Math Learning Center is “to inspire and enable individuals to discover and develop their mathematical confidence and ability.” It’s pretty easy to get behind a goal like that.

- Last but not least, the MLC staff might be the friendliest group of individuals I’ve ever met. To boot, they’re bright, hard-working, and dedicated to the organization’s mission.

With all that, the decision to join MLC was a rather easy one. If you can’t tell, I’m pretty excited about the change. I’ll be the new Chief Learning Officer, affectionately known as the **CLO**.

Time out for a puzzle.

Can you fill in the blanks to form a 16-letter math term that contains the letters CLO in order? Hint: think about transformational geometry or turning off the faucet.

_ _ _ _ _ _ _ C L O _ _ _ _ _ _

Relocating from Virginia to Oregon is a big deal. It’s nearly 2,800 miles — or 14 states, or 42 hours in a car — from our old house to our new one. Consequently, we hired a moving company to help with packing and shipping. When Lily from the moving company arrived, she asked if we had any “high-value items” to be transported, such as expensive jewelry or fur coats. (But not a real fur coat. That’s cruel.) I said that I didn’t think so, but then I asked what they consider a high-value item. Lily’s answer used a completely acceptable but surprising unit rate:

**anything over $100 per pound**

With that metric, it was suddenly obvious that we had several high-value items in our home. The first was a pair of diamond earrings that I had given my wife recently for our 15th anniversary. Since 5 carats = 1 gram, these small hunks of rock have a retail value of nearly $4,000,000 per pound, significantly above the moving company’s threshold.

The other high-value items were, well, *us*. The “value of statistical life,” or VSL, is a measure of the value of a human life. Its exact amount depends upon which federal agency you reference. The Environmental Protection Agency (EPA), for instance, pegs the VSL at $10 million. That means that I’m worth approximately $50,000 per pound, my petite wife is worth nearly $80,000 per pound, and our twin sons are worth well over $100,000 per pound each.

Granted, our value density isn’t as high as diamond, but we’re still pretty darn valuable.

A cannibal goes into a butcher shop, and he notices that the market specializes in brains. He sees that the butcher is selling engineer’s brain for $1.50 per pound, mathematician’s brain for $2.25 per pound, and politician’s brain for $375.00 a pound. Flabbergasted, he asks the owner why the huge difference in price. The butcher replies, “Do you have any idea how many politicians it takes to get a pound of brains?”

In the end, neither the diamond earrings nor any member of our family were loaded onto the moving truck. A week later, we’re adapting nicely to Portland culture, and I start my job at Math Learning Center in just a few days. Wish me luck!

### Silent Letter Night

Several weeks ago, Will Shortz presented an NPR Sunday Puzzle in which he stated a word and a letter, and the resulting collection would be rearranged to form a new word in which *the added letter is silent*. For instance, if Will gave RODS + W, the correct answer would be SWORD, in which the W is silent. (Note that the collection of letters is also an anagram of WORDS, but the W isn’t silent.)

At a time of year known for silent nights, it seems like a puzzle involving silent letters is completely appropriate. I’ve borrowed Shortz’s idea and extended it a bit; some of the clues in the list below have more than one silent letter added. Many items in the list are related to today’s holiday; and, because this is a math blog, the others are related to mathematics. In full disclosure, two of the answers are proper nouns.

Enjoy, and happy holidays!

- TO + W =
- TON + K =
- TOGS + H =
- GEE + D =
- TIN + G + H =
- SIN + G =
- SIN + E =
- CORD + H =
- HOLE + W =
- HEART + W =
- TINNY + E =
- COINS + E =
- NOELS + M =
- PILES + E + L =
- FRAME + T =
- REDACT + E + S + S =
- RACISMS + H + T =

### What’s in Your Pocket?

I recently received an email from adoring fan Alden Bradford:

Teacher: “Would you like a pocket calculator?”

Student: “No, thanks. I already know how many pockets I have.”

Thanks, Alden!

Of course, that reminded me of this gem from Spiked Math:

And one final pocket joke:

The department chair said to the math teachers, “I have good news, and I have bad news. The good news is, we have enough money for a new microwave in the staff lounge.” The teachers cheered! Then one of them asked, “What’s the bad news?” The chair said, “It’s still in your pockets.”

Ouch.

### Math Words for National Dictionary Day

Want to start today the right way? Say, “Good morning!” to Alexa today, and she’ll respond:

Good morning! It’s National Dictionary Day. Ever wonder what the shortest word is? Technically, it’s a toss-up between the single letter words

andI, but sinceais always capitalized, I’d sayIis just a little shorter.a

Is there anything more powerful than a language arts joke to get the day off to a good start?

I have no words to describe today. I do, however, have a ton of obscene gestures.

So, what’s the shortest **math** word? Technically, *e* and *i*, but if you don’t like constants, then you’ll have to settle for the three-letter words *set* and *box*.

And what’s the longest math word — at least based on the list at Math Words? It has 17 letters, and you’ll get a big hint if you check the time.

What two math words, both having the same number of letters, are equally appropriate to describe a triangle whose sides are congruent?

And what’s the funniest math word? Personally, I think it’s *syzygy*, but according to Tomas Engelthaler, it’s *logic*. In Humor Norms for 4,997 English Words, Engelthaler and Hills (2017) describe a method for determining which words are funniest. I emailed Engelthaler to ask which math word is funniest, and he responded as if it were a completely reasonable question. Without hesitation, he shared a list of math words and their humor rankings, and these five were at the top of the list:

- logic
- math
- theory
- science
- graph

The overall funniest English word, according to Engelthaler’s research? *Booty*. Go figure.

While you may not think that any of those words, mathy or otherwise, are laugh-out-loud funny, this isn’t debatable; it’s based on science.

If you take issue with this research, you’ll need to discuss it with Engelthaler and his colleagues. Please write to him directly to say that you’re bumfuzzled, that his research is malarkey, or that you think he’s a nincompoop.

### Required Summer Reading: *The Grasshopper King*

If you’ve read *How Not to Be Wrong: The Power of Mathematical Thinking*, then you know that Jordan Ellenberg is extremely intelligent, well educated, and incredibly talented. In addition, he may be the best voice for mathematics in America today. (You may have come to the same conclusion by reading his “Do The Math” column in *Slate* or from any one of the articles he’s written for *The New York Times* or *The Wall Street Journal*.) But if you haven’t read *The Grasshopper King*, a nonfiction novel that Ellenberg wrote in 2003, then you are absolutely missing out on his gifts as a pure writer. It’s the tale of Stanley Higgs, an internationally acclaimed professor of Gravinics at Chandler State University; Samuel Grapearbor, a graduate student at CSU; and the silent relationship that forms when Grapearbor is assigned to watch Higgs after he decides — for no obvious reason — to stop talking.

Coffee House Press claims that the novel is about “treachery, death, academia, marriage, mythology, history, and truly horrible poetry.” I mean, what’s not to love?

I bought *The Grasshopper King* because of how much I enjoyed *How Not to Be Wrong*, but I had no intention of enjoying it nearly as much as I did. From the first page, though, I was enthralled with Ellenberg’s style. To amalgamate several of the Amazon reviews, “this is an unusual book,” but it is beautiful because of “the finely tuned precision of the writing itself.”

This is not a math book, but occasionally Ellenberg turns a phrase that reminds you he’s a mathematician. When Grapearbor’s girlfriend claims that New York is ninety-five percent liars and snobs, he replies, “In Chandler City it’s ninety-nine. Point nine repeating.” Other times, he’ll include mathematical terms that are, in fact, completely appropriate and economical, but not altogether necessary:

a grasshopper, stirred by some unguessable impulse, heaved itself out of the drench mess, rose and fell in a perfect, inevitable

parabolawhoseinterceptwas the exposed stripe of Charlie’s backthe pressure of the water made

concentric circlesbehind my clenched-shut eyelidsthe agricultural buildings were at

discreet distancesfrom one another

And, yes, I know that last one isn’t a math phrase… but I can’t help but read it as *discrete distances*.

If you like Pynchon or Wolfe or anything off the beaten path, then you’ll like this book. The characters are quirky and memorable, and the writing is unforgettable. I recommend spending a few hours with it during what you have left of this summer.

### There Are 2 Things that Happened Yesterday…

Yesterday was a banner day.

Last night, I was finally able to carve out some time to binge-watch Season 2 of *Trial & Error*, and I was rewarded with a classic math joke in Episode 1. When lead investigator Dwayne Reed arrives at the house of accused murderer Lavinia Peck-Foster, he says:

There are two things that Reeds don’t trust: doctors, Pecks, and math.

I love it!

Upon realizing that I might be able to get my sitcom-writing career off the ground by reformulating stale math jokes, I promptly submitted my resume to NBC.

But, wait… there’s more!

Earlier in the day, I received NCTM‘s email newsletter *Summing Up*, which contained an unexpected surprise. In the section titled “NCTM Store,” there was a blurb about my most recent book, *More Jokes 4 Mathy Folks*, under the headline **Just Published!**

I had no idea that NCTM decided to sell my book, let alone that they were going to publicize it. My ignorance not withstanding, I couldn’t be more delighted!

If you’re looking for some great, light summer reading — something that can be enjoyed poolside while sipping a mojito — then pick up a copy of ** More Jokes 4 Mathy Folks** from NCTM today! Not only will your purchase support a great organization (and my sons’ college fund), you’ll also receive a 20% discount for being an NCTM member.

Following the lead of Dwayne Reed, here are jokes that begin, “There are *n* kinds…,” all of which appear in *More Jokes 4 Mathy Folks*:

- There are only 2 kinds of math books: those you cannot read beyond the first sentence, and those you cannot read beyond the first page. (C. N. Yang, Nobel Prize in Physics, 1957)
- There are 2 kinds of people in the world: those who don’t do math, and those who take care of them.
- There are 3 kinds of people in the world: positive, negative, and relative.
- There are 2 kinds of people in the world: those who are wise, and those who are otherwise.
- There are 2 kinds of statistics: the kind you look up, and the kind you make up.
- There are 2 kinds of experienced actuaries: those who say they have made significant forecasting errors, and liars.
- There are 10 kinds of people in the world: those who understand binary, and those who don’t.
- There are 10 kinds of people in the world: those who understand binary, and 9 others.
- There are 10 kinds of people in the world: those who understand ternary; those who don’t understand ternary; and, those who mistake it for binary.
- There are 11 kinds of people: those who understand binary, and those who don’t.
- There are 8 – 3 × 2 kinds of people in the world: those who correctly apply the order of operations, and those who don’t think that 6 ÷ 2 × (1 + 2) = 9.
- There are 2 kinds of people in the world: logicians and ~logicians.
- There are 2 kinds of people in the world: those who can extrapolate from incomplete data…