Nearly five years ago, I wrote about HIPE, a parlor game in which one person gives a particular string of letters, and the other people in the parlor try to guess a word with that same string of letters (consecutively, and in the same order).

Well, I recently rediscovered Can You Solve My Problems? by Alex Bellos, and I was pleasantly surprised to find that he included four HIPEs in that book:

  1. ONIG
  2. HQ
  3. RAOR

The fourth is one that I had included in my previous post, Don’t Believe the HIPE, and all are good enough that they deserve wide distribution.

Just for fun, here’s a new list of HIPEs that might prove interesting.

  • SSP
  • LWE
  • CUU
  • CTW
  • KGA
  • UIU
  • XII

In an effort to collect a bunch of excellent HIPEs, I’m asking for your help. If you play the game with friends and discover a particularly delectable combination of letters, please share below or at

January 17, 2020 at 6:54 am Leave a comment

Truth, Lies, and Math in Portland

The city that I now call home — Portland, OR — is the most beautiful city in the country. With views of Mt. St. Helens to the north, Mt. Adams to the northeast, Mt. Hood to the east, and powerful rivers through the middle of town, it’s hard to look in any direction without having your breath stolen.

As it turns out, Portland is also the smartest city in the country. This fact is irrefutable, per the following data.

Book Sales
Book Sales
per 100,000
New York32120.01.6
Los Angeles15813.31.2
San Francisco1434.73.0
Washington, DC1236.22.0

Although the data suggests that Portland might only be the second-smartest city in the country — Portland lags slightly behind Boston in per capita sales of Math Jokes 4 Mathy Folks — Stumptown leapfrogs Beantown because not a single person in Portland deigns to root for the Patriots.

The exemplary intelligence of Portlandians is only one of the many things I’ve discovered since moving to the Pacific Northwest. I’ve also learned that Portland is a beer Mecca; that, despite its reputation, the weather in Portland is far from terrible and, in fact, quite to my liking; it has some cool parks; and, Portland has a lot of bikes and a lot of bridges.


As a beer lover, I was ecstatic to hear that Portland had the most craft breweries of any city in the world.

Unfortunately, that was an old statistic, and Portland, OR, currently ranks #8 nationally in terms of craft breweries per capita:

  1. Portland, ME
  2. Asheville, NC
  3. Bend, OR
  4. Boulder, CO
  5. Kalamazoo, MI
  6. Vista, CA
  7. Greenville, SC
  8. Portland, OR
  9. Pensacola, FL
  10. Missoula, MT

The “other Portland” garners the top spot on the list. But it seems to me that if the list were culled to show only those cities where people actually want to live, the real Portland would again be near the top. (Asheville and Boulder absolutely give Portland a run for their money. But Kalamazoo and Vista? C’mon, now!)


Portland is known for gray skies and rain. But compare Portland to my previous hometown, Washington, DC.

The graphs below show that DC is warmer and wetter in the summer, but colder and drier in the winter.

But let’s dig into those numbers a little.

The average temperature in the two cities is remarkably similar, with Portland averaging 54.5°F and Washington, DC, averaging 55.7°F. But the hottest days are hotter in DC, and the coldest days are colder in DC. The temperate oceanic climate in Portland explains the cooler summers, the warmer winters, and the incredibly high number of homeless people.

Admittedly, Portland has more days of rain than Washington, DC — 156 to 115, in fact — but it receives a significantly smaller amount of rainfall — 36.0″ to 40.8″, a difference of nearly five inches.

Portland trails in hours of sunshine by roughly 10%, with 2,341 hours compared to DC’s 2,528. But Portland also has fewer days of snow per year, just 2.2 to DC’s 8.0, and much less accumulation — 3.0″ in Portland to a whopping 14.5″ in the nation’s capital.*

But rain, snow, sun, and temperature aside, there may be one statistic that is more important than all the others: Washington, DC, has significantly more days of Donald Trump, averaging over 300 per year since 2016; but since becoming President, Trump has spent nary a minute in Oregon.


Portland boasts Mill Ends Park, which holds the Guiness World Record for smallest park on the planet.

The smallest park in the world, Mill Ends Park in Portland, OR

With a diameter of just 24″, the total area of Mill Ends Park is exactly π square feet, or approximately 0.000 072 acres.


Portland has 94 miles of neighborhood greenways, 162 miles of bike lanes, and 85 miles of bike paths. That’s 341 biker‑friendly miles, which explains why more than 22,000 people ride their bikes to work every day. Over six percent of Portland’s commuters bike to work, which is twelve times the national average.

The joke in Portland is that, when you step off an airplane at PDX, they hand you a rain jacket and a dog. But if they really want folks to fit in, they better start doling out bikes, too.


The Willamette (pronounced wuh-LAM-it, not WILL-uh-met) River separates the east and west sides of Portland, and it’s spanned by twelve bridges. When the Hawthorne Bridge was built in 1910, it was one of the first vertical-lift bridges anywhere in the country; now, it’s the last one still in operation. The Tilikum Crossing Bridge was the country’s first ever multi-modal bridge that accommodated light rail, streetcar, buses, and pedestrians — but not private automobiles. And the St. John’s Bridge, known for its 400-feet high, twin Gothic-style arches, previously held the records for the world’s longest pre-stressed twisted rope cables as well as the tallest reinforced concrete pier in the world. 

St. John’s Bridge in NW Portland

Every morning as I cross the Sellwood Bridge, I look north to the smartest, drunkest, rainiest, most beautiful city in the country, and there’s no place I’d rather be.

* Every Portland resident who has relocated from some other part of the country will make a similar comparison between the weather in Portland and the weather in the city where they used to live. This is nothing more than rationalizing the decision to move to a city that only gets 144 days of sunshine a year.**

** Every Portland resident will also tell folks in other cities how bad the weather is, in an attempt to discourage others from moving to this amazing city. In short, they don’t want you here. I suspect, in fact, that they didn’t (and maybe still don’t) want me here. But too late, I’m staying. You, on the other hand, shouldn’t even think of coming here. I promise, you’ll hate it.

January 13, 2020 at 7:46 am Leave a comment

20 Math Problems for 2020

Happy New Year!

What’s so great about 2020?

  • It’s a leap year — yay!
  • It’s the end of the decade — how decadent!
  • It’s the year of the rat — squeak!
  • It’s an election year — okay, maybe it’s not that great of a year after all.

To get your mind thinking about something other than the associated realities of that last bullet, here are 20 problems to prepare you for the next 366 days.

  1. What’s the difference between the number of positive integer factors of 2020 and the number of positive integer factors of 2020?
  2. If all of the numbers from 1 to 2,020 were written down, how many digits would be used?
  3. If all of the numbers from 1 to 2,020 were spelled out, how many letters would be used?
  4. The numbers 1 through 2,020 are written on a whiteboard. At every stage, two numbers (say, a and b) are erased from the whiteboard and replaced with the sum a + b + 1. For example, if 187 and 2,013 were erased, then 187 + 2,013 + 1 = 2,201 would be written on the whiteboard. This process is repeated until a single number remains on the whiteboard. What is the number?
  5. How many positive integers are less than the square root of 2,020?
  6. How many different rectangles with integer side lengths and an area of 2,020 square units are possible?
  7. A lighthouse is perched on the cliff of a rocky beach. Standing in the lantern room of the lighthouse, you are approximately 2,020 feet above the surface of the ocean below. How far can you see to the horizon?
  8. A rectangular prism with integer edge lengths has a volume of 2,020 cubic centimeters. What is the maximum possible surface area of this solid?
  9. Mike made two initial bank deposits on Monday and Tuesday. Then every day for the rest of the week, he deposited an amount equal to the sum of the previous two days’ deposits. If he deposited $2,020 on Saturday, and his deposit on Monday was less than $10, what was the amounts of his deposit on Tuesday?
  10. What’s the sum of 101 + 202 + 303 + … + 2,020?
  11. How many postive, four-digit numbers can be formed with the digits 2, 0, 2, and 0?
  12. Saying that someone has 20/20 vision means they have normal visual acuity. That is, if you have 20/20 vision, then from 20 feet away, you can see what a normal person would see clearly from 20 feet away. In general, if you have 20/n vision, then from 20 feet away, you can see what normal people would see from n feet away. A person with 20/5 vision is looking at a billboard that is a mile away, and she can clearly see the letters on the billboard. How much closer would a person with 20/80 vision need to stand to clearly see the letters on the billboard? (Assume both people are standing at the boundary of where they can read the sign clearly.)
  13. A triangle has two sides of length 20. What is the maximum possible area of this triangle?
  14. Using only the digit 2 and the addition symbol, you can create expressions with many different values. For instance, you could use three 2’s and one addition symbol to make 22 + 2 = 24, or you could use  eight 2’s and three additional symbols to make 222 + 22 + 22 + 2 = 268. Using this process, what is the minimum number of 2’s needed to make an expression with a value of 2,020?
  15. In how many zeroes does the number 2020 end?
  16. Find the smallest possible string of consecutive positive integers that have a sum of 2,020.
  17. One integer is removed from the set {1, 2, 3, …, n} so that the sum of the remaining numbers is 2,020. What integer was removed?
  18. What is the product of the prime divisors of 2,020?
  19. What is the maximum possible product for a set of positive integers that have a sum of 2,020?
  20. Which of the following chains — each consisting of regular polygons with side length 1 unit — could be extended to have a perimeter of exactly 2,020 units?


  1. 849
  2. 6,973 digits
  3. 47,123 letters
  4. 2,043,229
  5. 44 integers
  6. 6 rectangles
  7. approximately 52.5 miles
  8. 8,082 square centimeters
  9. $401 on Tuesday (and $5 on Monday)
  10. 21,210
  11. 3 numbers
  12. the person would need to be 1/16 mile = 330 feet from the billboard, which is 4,950 feet closer
  13. 200 square units
  14. 29 2’s
  15. 20 zeroes
  16. 402, 403, 404, 405, 406
  17. 60
  18. 1,010
  19. 3672 × 22
  20. only the squares; for n squares, the perimeter is 2n + 2, and n = 1,009 yields a perimeter of 2 × 1,009 + 2 = 2,020

January 1, 2020 at 12:01 am Leave a comment

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.

Chuck Norris as Walker Texas Ranger
Chuck Norris as Walker, Texas Ranger

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.

December 22, 2019 at 8:53 am Leave a comment

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.

No-Op KenKen puzzle with target numbers from today's date
A 4 × 4 no-op KenKen puzzle with target numbers from today’s date

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!

December 17, 2019 at 5:52 am Leave a comment

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, 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 x2 + 2x + 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 obtuse triangle, because I’m never right.

November 15, 2019 at 5:53 am Leave a comment

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.

MLC LogoAfter 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.


Precious Cargo

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!

August 8, 2019 at 5:10 am Leave a comment

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About MJ4MF

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.

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