## Posts tagged ‘math’

### 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…

### Stick Figure Math

I’ll never forget the first time I saw the pattern

1, 2, 4, 8, 16, __

and was dumbfounded to learn that the missing value was 31, not 32, because the pattern was not meant to represent the powers of 2, but rather, the number of pieces into which a circle is divided if n points on its circumference are joined by chords. Known as Moser’s circle problem, it represents the inherent danger in making assumptions from a limited set of data.

Last night, my sons told me about the following problem, which they encountered on a recent math competition:

What number should replace the question mark?

Well, what say you? What number do you think should appear in the middle stick figure’s head?

Hold on, let me give you a hint. This problem appeared on a multiple-choice test, and these were the answer choices:

1. 3
2. 6
3. 9
4. 12

Now that you know one of those four numbers is supposed to be correct, does that change your answer? If you thought about it in the same way that the test designers intended it, then seeing the choices probably didn’t change your answer. But if you didn’t think about it that way and you put a little more effort into it, and you came up with something a bit more complicated — like I did — well, then, the answer choices may have thrown you for a loop, too, and made you slap your head and say, “WTF?”

For me, it was Moser’s circle problem all over again.

So, here’s where I need your help: I’d like to identify various patterns that could make any of those answers seem reasonable.

In addition, I’d also love to find a few other patterns that could make some answers other than the four given choices seem reasonable.

For instance, if the numbers in the limbs are a, b, c, and d, like this…

then the formula 8a – 4d gives 8 for the first and third figures’ heads and yields 8 × 6 – 4 × 9 = 12 as the answer, which happens to be one of the four answer choices.

Oh, wait… you’d don’t like that I didn’t use all four variables? Okay, that’s fair. So how about this instead: ‑3a + b + c – 2d, which also gives ‑3 × 6 + 7 + 5 + 2 × 9 = 12.

[UPDATE (3/9/18): I sent a note to the contest organizers about this problem, and I got the following response this afternoon: “Thanks for your overall evaluation comments on [our] problems, and specifically for your input on the Stick Figure Problem. After careful consideration, we decided to give credit to every student for this question. Therefore, scores will be adjusted automatically.”]

### 2017 KenKen International Championship

If you like puzzles and ping pong, then Pleasantville, NY, was the place to be on December 17.

More than 200 Kenthusiasts — people who love KenKen puzzles — descended on Will Shortz’s Westchester Table Tennis Center for the 2017 KenKen International Championship (or the KKIC, for short). Participants followed 1.5 hours of solving KenKen puzzles with a pizza party and several hours of table tennis.

The competition consisted of three rounds, with the three puzzles in each round slightly larger and more difficult than those from the previous round. Consequently, competitors were given 15, 18, and 20 minutes to complete the puzzles in the first, second, and third rounds, respectively.

Competitors earned 1,000 points for each completely correct puzzle, and 0 points for an incomplete or incorrect puzzle. In addition, a bonus of 5 points was earned for every 10 seconds in which a puzzle was turned in before time was called. So, let’s say you got two of the three puzzles correct and handed in your answers with 30 seconds remaining in the round; then, your score for that round would be

$2 \times 1000 + \frac{30}{10} \times 5 = \bf{2{,}015}$

The leader after the written portion was John Gilling, a data scientist from Brooklyn, whose total score was 10,195. And if you’ve been paying attention, then you know what that means — Gilling earned 9,000 points for completing all of the puzzles correctly, so his time bonus was 1,195 points… which is the amount you’d earn for turning in the puzzles 2,390 seconds (combined) before time was called. The implication? Gilling solved all 9 puzzles from the written rounds — which contained a mix of puzzles from size 5 × 5 to 8 × 8 — in just over 13 minutes.

Wow.

As a result, Gilling, the defending champion, earned a spot in the Championship Round against Tess Mandell, a math teacher from Boston; Ellie Grueskin, a high school senior at The Hackley School; and Michael Holman, a technology consultant. In the final round, each of them attempted a challenging 9 × 9 puzzle, which was displayed on an easel for the crowd to see. Solving a challenging 9 × 9 is tough enough; having to do it as 200 kenthusiasts follow your every move is even tougher.

So, how’d they do? See for yourself…

When the dust settled, Gilling had successfully defended his title. For his efforts, he received a check for \$500. But more importantly, he retained bragging rights for one more year.

John Gilling and his winning KenKen board at the 2017 KKIC

If you think you’ve got what it takes to compete with the best KenKen solvers, try your hand at the 9 × 9 puzzle that was used in the final round. In the video above, you saw how fast Gilling solved it to win the gold. But even the slowest of the four final-round participants finished in under 15 minutes.

Again, wow.

Finally, I’d be failing as a father if I didn’t mention that my sons Alex and Eli competed in the Delta (age 10 and under) division. Though bested by Aritro Chatterjee, a brilliant young man who earned a trip to the 2017 KKIC by winning the UAE KenKen Championship, Eli took the silver, and Alex brought home the bronze. They’re shown in the photos below with Bob Fuhrer, the president of Nextoy, LLC, the KenKen company and host of the KKIC.

#proudpapa

For more KenKen puzzles, check out www.kenken.com, or see my series of posts, A Week of KenKen.

### Number Challenge from Will Shortz and NPR

Typically, the NPR Sunday Puzzle involves a word-based challenge, but this week’s challenge was a number puzzle.

[This challenge] comes from Zack Guido, who’s the author of the book Of Course! The Greatest Collection of Riddles & Brain Teasers for Expanding Your Mind. Write down the equation

65 – 43 = 21

You’ll notice that this is not correct. 65 minus 43 equals 22, not 21. The object is to move exactly two of the digits to create a correct equation. There is no trick in the puzzle’s wording. In the answer, the minus and equal signs do not move.

Seemed like an appropriate one to share with the MJ4MF audience. Enjoy!

### The Remote Associates (RAT) and Close Associates (CAT) Tests

The Remote Associates Test (RAT) is a test used to determine a person’s creative potential. When given a collection of three seemingly unrelated words, subjects are asked to supply a fourth word that is somehow related to each of the three stimulus words. For example, if you were given the words cottage, swiss, and cake, you’d answer cheese, because when combined with the three stimuli, you get cottage cheese, swiss cheese, and cheesecake.

To try your hand at one of these tests, you can head to remote-associates-test.com, or you can just keep on reading.

The verdict is out as to whether a high score on the RAT actually means you’re more creative. But what’s not in doubt is how much I love to solve, and to create, these items. It’s a good game for long car rides, and my wife, sons, and I can amuse ourselves for hours by creating and sharing them with one another.

For your enjoyment, I present the following mathematical RAT test: The fourth word related to the three stimulus words in each set is a common math term. Enjoy!

1. attack / acute / fish
2. inner / around / full
3. phone / one / mixed
4. powers / rotational / point
5. up / on / hot
6. tipping / blank / selling
7. even / duck / couple
8. black / Bermuda / love
9. inkhorn / limits / short
10. sub / hour / tolerance
11. world / television / infinite
12. ball / camp / data
13. Dracula / head / sheep
14. field / dead / stage
15. town / off / meal
16. air / hydro / geometry
17. common / X / fudge
18. key / bodily / dis
19. disaster / 51 / grey
20. ball / S / hairpin

The Close Associates Test (CAT) is a similar, yet completely fictitious, test that I just made up. Each item on a CAT test contains three words which do not appear to be unrelated in the least; in fact, they are so closely related that finding the fourth word they have in common is somewhat trivial. The following mathematical CAT test will not measure your creativity, though it might reasonably determine the depth of your mathematical vocabulary. Good luck!

1. acute / obtuse / right
2. scalene / equilateral / isosceles
3. sine / logistic / regression
4. real / irrational / whole
5. proper / improper / reduced
6. convergent / infinite / divergent
7. in / circum / ortho
8. Pythagorean / De Moivre’s / Ramsey’s
9. exponential / differential / Diophantine
10. convex / concave / regular
11. golden / common / test
12. square / cube / rational

1. angle
2. circle
3. number
4. axis
5. line
6. point
7. odd
8. triangle
9. term
10. zero
11. series
12. base
13. count
14. center
15. square
16. plane
17. factor
18. function
19. area
20. curve

1. angle
2. triangle
3. curve
4. number
5. fraction
6. series
7. center
8. theorem
9. equation
10. polygon
11. ratio
12. root

Feel free to submit more triples for the RAT or CAT test in the comments.

### 8-15-17

Today is a glorious day!

The date is 8/15/17, which is mathematically significant because those three numbers represent a Pythagorean triple:

$8^2 + 15^2 = 17^2$

But August 15 has also been historically important:

But as of today, August 15 has one more reason to brag: It’s the official publication date of a bestseller-to-be…

Like its predecessor, this second volume of math humor contains over 400 jokes. Faithful readers of this blog may have seen a few of them before, but most are new. And if you own a copy of the original Math Jokes 4 Mathy Folks, well, fear not — you won’t see any repeats.

What kind of amazing material will you find on the pages of More Jokes 4 Mathy Folks? There are jokes about school…

An excited son says, “I got 100% in math class today!”

“That’s great!” his mom replies. “On what?”

The son says, “50% on my homework, and 50% on my quiz!”

There are jokes about mathematical professions…

An actuary, an underwriter, and an insurance salesperson are riding in a car. The salesperson has his foot on the gas, the underwriter has her foot on the brake, and the actuary is looking out the back window telling them where to go.

There are Tom Swifties…

“13/6 is a fraction,” said Tom improperly.

And, of course, there are pure math jokes to amuse your inner geek…

You know you’re a mathematician if you’ve ever wondered how Euler pronounced Euclid.

Hungry for more? Sorry, you’ll have to buy a copy to sate that craving.

To purchase a copy for yourself or for the math geeks in your life, visit Amazon, where MoreJ4MF is already getting rave reviews:

For quantity discounts, visit Robert D. Reed Publishers.

### Just Sayin’

Heidi Lang is one of the amazing teachers at Thomas Jefferson Elementary School. When she’s not challenging my sons with interesting puzzles and problems, she’s entertaining them with jokes that make them think. On her classroom door is a sign titled Just Sayin’, under which hangs a variety of puns. Here’s one of them:

Last night, I was wondering why I couldn’t see the sun. Then it dawned on me.

That reminds me of one of my favorite jokes:

I wondered why the baseball kept getting larger. Then it hit me.

Occasionally, one of her puns has a mathematical twist:

Did you know they won’t be making yardsticks any longer?

And this is one of her mathematical puns, though I’ve modified it a bit:

When he picked up a 20‑pound rock and threw it 5,280 feet, well, that was a real milestone.

I so enjoy reading Ms. Lang’s Just Sayin’ puns that I decided to create some of my own. I suspect I’ll be able to hear you groan…

• He put 3 feet of bouillon in the stockyard.
• When the NFL coach went to the bank, he got his quarterback.
• She put 16 ounces of poodle in the dog pound.
• The accountant thought the pennies were guilty. But how many mills are innocent?
• His wife felt bad when she hit him in the ass with 2⅓ gallons of water, so she gave him a peck on the cheek.
• Does she know that there are 12 eggs in a carton? Sadly, she dozen.
• When his daughter missed the first 1/180 of the circle, he gave her the third degree.
• She caught a fish that weighed 4 ounces and measured 475 nm on the visible spectrum. It was a blue gill.
• When Rod goes to the lake, he uses a stick that is 16.5 feet long. He calls it his fishing rod.
• What is a New York minute times a New York minute? Times Square.
• I wanted to dance after drinking 31 gallons of Budweiser, so I asked the band to play the beer barrel polka.
• The algebra teacher was surprised by the mass when she tried to weigh the ball: b ounces.

And because this post would feel incomplete without it, here’s probably the most famous joke of this ilk:

• In London, a pound of hamburger weighs about a pound.

The Math Jokes 4 Mathy Folks blog is an online extension to the book Math Jokes 4 Mathy Folks. The blog contains jokes submitted by readers, new jokes discovered by the author, details about speaking appearances and workshops, and other random bits of information that might be interesting to the strange folks who like math jokes.

## MJ4MF (offline version)

Math Jokes 4 Mathy Folks is available from Amazon, Borders, Barnes & Noble, NCTM, Robert D. Reed Publishers, and other purveyors of exceptional literature.