Posts tagged ‘beer’

IDK Puzzles

I like logic, and I like beer, so it’s no surprise that this is one of my favorite online comics:

Not sure why that’s funny? There’s an explanation at

Logic puzzles in which a protagonist states, “I don’t know!” are ubiquitous. Borrowing from texting culture, I’ve taken to calling these IDK Puzzles.

Every math person remembers the first non-routine problem they solved and, more importantly, the feeling they experienced when solving it. The first time I had that feeling occurred after solving a logic puzzle about three children’s ages that I discovered in a Martin Gardner book; now many years later, I don’t remember the title of the book, and the following is my best recollection of the puzzle:

Two neighbors are speaking. One asks the other, “I know you have three children, but how old are they?”

The other says, “The product of their ages is 72.”

The first neighbor says, “I still don’t know their ages.”

“Well,” says the other, “the sum of their ages is equal to our street address.”

The first neighbor again replies, “I still don’t know their ages.”

“I’m sorry,” says the other, “I can’t talk anymore, because I have to take my oldest child to the dentist,” and then leaves.

While saying good-bye, the first neighbor thinks, “Ah, now I know their ages.”

This puzzle is typical of the genre, in that it appears there is insufficient information, but those who persist will be rewarded. Can you figure out the three children’s ages?

A slightly different IDK Puzzle involves geometric shapes.

Two people are shown the following five shapes:

They are told that a prize has been placed under one of the shapes. One of the people is told the color, and the other is told the shape, but they are not allowed to share their information with each other.

They are asked, “Do either of you know where the prize is hidden?”

Both of them reply, “I don’t know.”

They are asked a second time, “Do either of you know where the prize is hidden now?”

Again, they both reply, “I don’t know.”

They are asked a third time, “What about now?”

They both reply, “Yes!”

Under what shape has the prize been hidden?

Enjoy solving those puzzles. Staying with the theme, let’s end this post with a logic joke of sorts…

Sam comes home from the grocery store with twelve gallons of milk. Pam asks, “Why’d you buy so much milk?”

“Because before I left, you told me to buy a gallon of milk, and then you said, ‘If they have eggs, buy a dozen.’ And they had eggs.”

Pam shakes her head at Sam’s response. But then she notices he hasn’t bought anything else and asks, “Where are the rest of the things we needed?”

“Remember how you told me to put ketchup on the list?” replies Sam.

“Yeah. So?”

“So I put ketchup on the list, but then I couldn’t read the other items!” Sam says. “But I remembered the eggs!”

April 12, 2022 at 4:56 am Leave a comment

The Beer Paradox

Beer Taps

From Gene Weingarten’s recent column, “Rhymes Against Humanity,” in the January 28 edition of the Washington Post Magazine:

An infinite number of mathematicians
Walked into a bar on one recent night,
And, under the strangest of barroom conditions,
What followed quite nearly became a big fight.

“I’ll have a pint,” said the first to the ’tender.
“I’ll have a half,” said the next fellow down.
“I’ll have a quarter,” said the third (no big spender).
“Give me an eighth,” said the next, like a clown.

The bartender fumed and grew suddenly pale
Then, calmly, he turned and he went to the spout
Drew up two pints, set them down at the rail.
Said, “Enough of this nonsense — you all work it out.”

This is an MJ4MF original, though like Gene’s, it’s based on a stale, old joke:

With my head in an oven
And my feet on some ice,
I’d say that, on average,
I feel rather nice!

What other classic math jokes can be easily converted to poems? Or have already been?

January 29, 2018 at 11:38 pm 2 comments

All Systems Go

I noticed the boys having an intense conversation in front of this sign at our local pizza shop:

Flippin Pizza Sign

When I asked what they were doing, they said, “We’re trying to figure out how much one slice and a beer would cost.”

As you read that, there were likely two thoughts that crossed your mind:

  • Why can’t these poor boys look at a pizza menu without perceiving it as a system of equations?
  • Why are eight-year-olds concerned with the price of beer?

The answer to both, of course, is that I’m a terrible father, and both beer and math are prominent in our daily lives.

But you have to admit that it’s pretty cool that my sons recognized, and then solved, the following system:

\begin{array}{rcl}  2p + s & = & 6.00 \\  2p + b & = & 8.00 \\  p + s & = & 3.50 \end{array}

They didn’t use substitution or elimination because they didn’t have to — and, perhaps, because they don’t know either of those methods yet. But mental math was sufficient. If two slices and a soda cost $6.00, and one slice and a soda cost $3.50, then one slice must be 6.00 – 3.50 = $2.50. Consequently, two slices cost $5.00, so a beer must be 8.00 – 5.00 = $3.00. A beer and a slice will set you back $5.50.

I remember once visiting a classroom in Somerville, MA, and the teacher was reviewing the substitution method. My memory is a bit fuzzy, but the problem she solved on the chalkboard was something like this:

Mrs. Butterworth’s math test has 10 questions and is worth 100 points. The test has some true/false questions worth 8 points each and some multiple-choice questions worth 12 points each. How many multiple-choice questions are on the test?

The teacher then used elimination to solve the resulting system:

\begin{array}{rcl}  t + m & = & 15 \\  5t + 10m & = & 100 \end{array}

The math chairperson was standing next to me as I watched. “Why is she doing that?” I asked. “You don’t need elimination. It’s clear there have to be 8 or fewer multiple-choice questions (8 × 12 = 96), so why not just guess-and-check?”

“Because on the MCAS [Massachusetts Comprehensive Assessment System], if they tell you to use elimination but you solve the problem a different way, it’ll be marked wrong.”

So much for CCSS.Math.Practice.MP1. Although most of us would like students to “plan a solution pathway rather than simply jumping into a solution attempt,” apparently students in Massachusetts need to blindly follow algorithms and not think for themselves.

The following is my favorite system of equations problem:

I counted 34 legs after dropping some insects into my spider tank. How many spiders and how many insects?

Why is this my favorite system of equations problem? Because there is a unique solution, even though it results in just one equation with two unknowns. Traditional methods won’t work, and students have to think to solve it. Blind algorithms lead nowhere.

Other things that lead nowhere are spending your leisure hours reading a math jokes blog. But since you’re here…

Why did the student put his homework in a fish bowl?
He was trying to dissolve an equation.

An engineer thinks that his equations are an approximation to reality. A physicist thinks reality is an approximation to his equations. A mathematician doesn’t care.




April 22, 2016 at 2:56 pm 3 comments

Math for International Beer Day

I don’t need an excuse to do math. Nor do I need one to drink beer.

But if I did, today is IBD.

International Beer Day

I’m most happy when I can pursue my two passions simultaneously…

Root Beer Squared

That said, I never attempt calculus while imbibing. It’s not safe to drink and derive.

And like most of the American populace, I almost never attempt to think logically while drinking beer…

A bartender asks three logicians, “Would all of you like beer?”
The first answers, “I don’t know.”
The second answers, “I don’t know.”
The third answers, “Yes!”

August 1, 2014 at 1:16 am 2 comments

All Beer and Skittles

The winter has been unkind to my waist, so I joined a month-long fitness challenge at the gym. I asked one of the trainers what I should do to win. “Drink 25 beers on Saturday night,” he said.


“Because the weigh-in is Sunday morning, and you want to be heavy as possible.”

“Yeah, I get that,” I replied. “But there are 24 bottles in a case. Okay if I stop there?”

How many is too many? Hard to say…

Teacher: If I had 5 bottles in one hand and 6 bottles in the other hand, what would I have?
Student: A drinking problem?

With St. Patrick’s Day just around the corner, here are a few more beer jokes.

If you pour root beer in a square cup, will it become beer?

And who doesn’t like a joke that makes fun of professors?

A literature professor, a computer scientist, and a mathematician head to a pub. They each order a pint of beer, and when the drinks are brought to the table, each pint has a fly in it.

The literature professor pushes her beer away in disgust.

The computer scientist removes the fly and proceeds to drink his beer.

The mathematician picks the fly out of his drink, too, but then holds it out over the beer and yells, “Spit it out, you little bastard!”

March 13, 2014 at 10:14 pm 2 comments

Rootin’ Around

The digits of today’s date can be concatenated to make the four-digit number 4913, and 4913 = 173. As it turns out, this is the only date in 2013 for which the concatenation of the digits forms a number that has a square, cube, fourth, fifth, or sixth root that is a whole number.

I’m sure there are more useless pieces of trivia, but I can’t think of one right now.

[Update, 4/9/13: Perhaps the following isn’t more useless, but it’s certainly not more useful, either. I failed to mention the trivial numerology contained within today’s date: 4 + 9 = 13.]

In any case, this fact about the cube root of 4913 got me to thinking about some of my favorite things.

My favorite drink:

Root Beer

My favorite highway:

Root 66

My favorite LeVar Burton movie:


My favorite types of efforts:

Grass Roots

My favorite idiom:

Putting Down Roots

April 9, 2013 at 1:10 am 5 comments

Upside-Down Tooth Numbers

Alex and Eli know that 15 ÷ 3 = 5, that 63 ÷ 7 = 9, and, given a little time, could figure out that 104 ÷ 8 = 13. That’s not bad for five-year-olds.

As we were discussing sharing a treat the other day, we naturally happened upon a situation in which it would be good to know what 1 ÷ 2 is.

Alex suggested, “Two.”

I explained that while the order of the numbers in multiplication doesn’t matter — for example, 2 × 3 = 3 × 2 — order does matter with division. I used the word commutative, but I also tried to explain it with plainer language, too.

I took a rectangular piece of paper and ripped it in half. “How big is each piece?” I asked. The both knew it was one-half. “So there you have it: 1 ÷ 2 = 1/2.”

But why stop there? I divided one of the halves in half again, and I asked, “How big is this piece?” They both knew it was one-quarter. “So that shows that 1/2 ÷ 2 = 1/4.”

They saw that if we continued in this manner, we would get 1/8, 1/16, 1/32, and so on, a pattern they called the upside-down tooth numbers, because the numbers in the sequence are the reciprocals of the powers of two. (For them, tooth = 2th.)

Looking at the pieces of paper on the table, I asked a more advance question. “What do you think we’d get if we added 1/2 + 1/4 + 1/8 + 1/16 + 1/32 + …, and we kept adding half as much each time?”

Eli thought for a few seconds. “I think it would be one whole,” he offered.

I was surprised. “Why?” I asked.

“Well,” he said, “I’m thinking about a circle.”

I looked at the rectangular pieces of paper on the table, which had nothing to do with a circle. Sure, he got the right answer, but his reasoning is way off base, I thought.

He explained further. “If you fill half a circle, then a quarter more, then an eighth, and keep going, you’ll eventually fill the whole thing. That’s why I think it’s one.”

Visually, Eli’s argument would look something like this…

Infinite Series - One Half

Holy sh*t, I thought. That’s pretty good for a five-year-old.

I don’t even care that he doesn’t understand this joke:

An infinite number of mathematicians walk into a bar. The first asks for half a beer. The second asks for a quarter of a beer. The third asks for an eighth of a beer. The bartender interrupts, pours one beer for them, and says, “You guys don’t know your limits.”

I think I was so impressed with Eli’s solution because infinite series can be difficult, even for mathy professionals:

A mathematician will call an infinite series convergent if its terms go to zero. An engineer will call it convergent if the first term is finite.

And let us not forget the Eilenburg swindle, which proves that 1 = 0 since:

1 − 1 + 1 − 1 + … = 1 + (−1 + 1) + (−1 + 1) + … = 1


1 − 1 + 1 − 1 + … = (1 − 1) + (1 − 1) + … = 0

Related to all this, there is a perhaps apocyphal story in which it is rumored that a student once posed the following problem to John von Neumann:

Two trains begin a mile apart and head towards each other at 60 miles an hour. A fly on one train flies at 120 mph to the other train, and when it touches the other train, it immediately turns around and flies back to the first train, and so on, flying back and forth between the two trains until it gets squashed in the middle. How far does the fly travel?

von Neumann thought about it a moment and said, “One mile.” The student said to von Neumann that most people don’t realize that the problem can be figured out easily: the trains meet in 30 seconds, and the fly can travel one mile in half a minute; yet most people think they have to add up the infinite series to figure out how far the fly travels. As the story goes, von Neumann replied, “But that’s how I did it.”

November 30, 2012 at 1:45 pm Leave a comment

Beer and Calculus Don’t Mix — Don’t Drink and Derive!

After Franklin Delano Roosevelt signed the Cullen-Harrison Act to end prohibition, sales of beer in the U.S. became legal on April 7, 1933. (Not a moment too soon, I might add. My father was born on April 12, 1933, and he surely gave my grandmother plenty of reasons to imbibe!) Consequently, April 7 is now known as National Beer Day, and April 6 is unofficially New Beer’s Eve.

A definite integral walks into a bar and orders five pints of Guinness. The bartender pours them, and the definite integral finishes them one after the other. “Can I have five more?” he asks.

The bartender says, “Don’t you think you’ve had enough?”

“Don’t worry about me,” says the integral. “I know my limits.”

Someday, I hope to meet the guy who invented beer — and buy that man a beer!

Finally, a logic puzzle with a solution that seems appropriate…

You come to a fork in the road. One branch leads to the City of Truth, and the other leads to the City of Deceit. You can ask the person stationed at the fork in the road one simple question to help you determine the correct path to the City of Truth. If the person is from the City of Truth, he will answer your question honestly; if he is from the City of Deceit, he will answer your question dishonestly. What question should you ask?

“Did you know they’re serving free beer in the City of Truth?”

The truth‑teller will say, “No!” and run to get a beer. The liar will say, “Yes!” and run to get a beer. Either way, follow him.

April 6, 2011 at 12:41 am 4 comments

Drink It Green!

Green BeerToday is St. Patrick’s Day, of course, but at 9:33am, my mother’s baby boy celebrated the 40th anniversary of his birth. (Yes, I’m a cliche. I was born on St. Patrick’s Day, and my parents named me Patrick. But it was for the best, really — before my exact birthdate was known, the leading name candidate was George William, Jr. Yecch.)

Here’s an appropriate math joke for a beer-filled holiday:

An infinite number of mathy folks walk into a bar. The first one goes up to the bar and orders a pint. The second one goes up and orders half a pint. The third orders 1/4 pint. The fourth orders 1/8 pint, and so forth. A little overwhelmed, the bartneder asks them, “Hey, are you guys sure you want to do this? Isn’t that a bit much?”

The mathy folks reply, “Don’t worry. We know our limits.”

And some other jokes for a day dedicated to drinking…

Charles Dickens walks into a bar and orders a martini. The bartender asks, “Olive or twist?”

René Descartes is sitting in a bar. The bartender asks if he’d like another. “I think not,” says Descartes, and he promptly disappears.

An absent-minded math professor walks up to an attractive woman at the bar. “So, tell me,” he says, “do I come here often?”

A guy walks into a bar with a lizard on his shoulder. “What do you call that?” asks the bartender. “Tiny,” says the guy, “because he’s my newt.”

Okay, enough of that nonsense. Happy St. Patrick’s Day! Have a pint or two for me.

March 17, 2011 at 11:24 am Leave a comment

An Hour Left to Live

I’ve been thinking about my bucket list — you know, a list of all the things I want to do before I die — and some day I’ll get around to posting it. But perhaps more interesting is a list of the things I’d do if I had just one hour left to live…

  • Calculate how much time I have left in minutes and seconds. The first time would take less than a second — of course, it’s 60 minutes = 3,600 seconds. But then I’d have used a second, and I’d probably spend a couple more seconds wondering why I bothered to retain such useless trivia, at which point I’d need to update my calculation. So the second time I’d actually have to put a little thought into it, and the computation would actually take a few seconds to complete, and by the time I realized that I had 59 minutes, 24 seconds = 3,564 seconds remaining, I’d wonder why I’d wasted 1% of my time calculating how much time I had left. To avoid wasting any more time, I’d write a program to perform the calculations automatically and display the amount of time remaining. That would only take a few minutes, surely, but then there’s the debugging. Ah, those damn bugs! And since this will be my last program ever, I’d want it to be really cool, so I’d create an animation that shows a guy riding a unicycle along a hilly trail, up and down and up and down, and then, with just a few seconds left, the rider would pedal really fast up a large hill and launch himself into the stratosphere, and I’d watch him float into space as my time expires. And as I take my last breath, one thought would fill my head: “Wow. I only had an hour left — and I managed to waste that one, too.” 
  • Write a blog post explaining how I’d spend my last hour.
  • Complete the hardest Sudoku puzzle I can find — and then remember that I really, really, really despise Sudoku. (Yes, I know that’s blasphemous.)
  • Play Ultimate frisbee.
  • Spend it with my wife and sons, just hanging out.
  • Prove the Riemann Hypothesis. (I know I could do it. I do my best work under extreme pressure.)
  • Wonder how it is that I have so many good ideas in my head, yet the only book I authored during my lifetime was Math Jokes 4 Mathy Folks.
  • Take approximately 10 minutes to drink each beer from a mixed six-pack which would contain one each of the following: Dogfish Head 90 Minute Imperial Pale Ale; Clipper City Heavy Seas Loose Cannon Ale; Founders Breakfast Stout; Terrapin Gamma Ray; Jolly Pumpkin Oro de Calabaza; and, of course, Guinness Extra Stout Draught. In fact, on the off-chance that I ever find myself in this very situation, it would really suck to find that I didn’t have such a six-pack in my fridge. Consequently, I am leaving right now to purchase my “Apocalypse Pack.” Later…

January 12, 2011 at 8:36 am 2 comments

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.

Past Posts

September 2022

Enter your email address to subscribe to the MJ4MF blog and receive new posts via email.

Join 469 other followers

Visitor Locations

free counters