## Posts tagged ‘alphabet’

### Math Puzzles with Letters

This week on the NPR Sunday Puzzle, host Will Shortz offered the following challenge:

Name a famous city in ten letters that contains an

s. Drop thes. Then assign the remaining nine letters their standard value in the alphabet — A = 1, B = 2, C = 3, etc. The total value of the nine letters is only 25. What city is it?

It’s not much of a spoiler to note that the average value of those nine letters must be less than three, since their sum “is only 25.” Consequently, a lot of those letters must occur at the beginning of the alphabet and — if eight of them were *a*‘s — there would be no letters later than *q* in the name of the city. But that’s as much as I’ll say; you can solve the puzzle on your own. (When you do, you can submit your answer for a chance to play next week’s on-air puzzle live with Will Shortz.)

Mathematician Harold Reiter uses a similar problem with elementary school students. Using the same idea — that each letter has a value (in cents) equal to its position in the alphabet — he asks students to find a dollar word, that is, a word whose letters have a sum of 100. As it turns out, there are many. Based on a nonexhaustive search, there are at least 3,500 dollar words, and likely a whole lot more. In a quick perusal of the list, one word jumped out: **oxygon**. Nope, that’s not a typo. It’s an archaic term meaning “a triangle with three acute angles.”

All of this talk of letters reminds me of my favorite puzzle, which I call Product Values. Using the same scheme — that is, A = 1, B = 2, C = 3, etc. — find the product value of a word by *multiplying* the values of the letters. So, for instance, *cat* has a product value of 3 × 1 × 20 = 60. How many words can you find that have a product value of 100? Based on the ENABLE word list, there are nine. (If you need some help, you can use the Product Value Calculator at www.mathjokes4mathyfolks.com.)

To end this post, a few math jokes that involve letters:

And Satan sayeth, “Let’s put the alphabet in math.” Bwa-ha-ha-ha-ha.

Romans had no trouble with algebra, because X was always equal to 10.

### One-Letter Quiz

The answer to each question below is a letter of the alphabet. Each letter is used exactly once. (Thanks for the idea, *Ask Me Another*.) Good luck!

**Want to amuse your friends, irritate your students, or annoy people you’ve just met? Download a ****PDF version of the One-Letter Quiz**** (without answers).**

- The letter used to represent the square root of -1.
- This letter is often added to indefinite integrals to show that any function with at least one antiderivative has an infinite number of them.
- The most frequently occurring letter in English words.
- The letter most recently added to the modern, 26-letter English alphabet.
- The letter represented by four dots in Morse Code.
- A type of road intersection with three arms.
- Although long out of use, this letter was used in the middle ages as the Roman numeral to represent 90.
- This letter is used for the temperature scale in which the boiling point is 212 degrees and the freezing point is 32 degrees.
- The most common blood type.
- The rating from the Motion Picture Association of America that requires children under 17 to be accompanied by an adult.
- The 43rd President of the United States.
- The only vowel that does not appear in the spelling of any single-, double-, or triple-digit numbers.
- Between
*s*and*c*, the second most common letter with which English words begin. - With
*plan*, the letter used to refer to a typically less desirable alternative. - The Roman numeral for 500.
- The symbol for potassium on the periodic table.
- The most common variable in algebra.
- The Roman numeral for 5.
- The “score” used to indicate the number of standard deviations a data point is from the mean.
- The letter commonly used to refer to the vertical axis on a coordinate graph.
- Although every adult can recognize the loop-tail version of this lowercase letter in print, less than one-third of participants in a Johns Hopkins study could correctly pick it out of a four-option lineup.
- The clothing size that increases when preceded by an X.
- The shape of the “happiness curve,” which implies that most people are least happy in their 50’s.
- The shape of a logistic growth curve, which increases gradually at first, more rapidly in the middle, and slowly at the end, leveling off at a maximum value after some period of time.
- The only letter that does not appear in the name of any US state.
- The answer to the riddle, “It occurs once in a minute, twice in a moment, but never in a thousand years.”

**Answers (and Notes of Interest)**

- I
- C
- E
- J : in 1524, Gian Giorgio Trissino made a clear distinction between the sounds for
*i*and*j*, which were previously the same letter - H
- T
- N : see Wikipedia for a list of other Roman numerals used in medieval times
- F
- O
- R
- W : should probably be “Dubya” instead of “Double U,” but whatever
- A
- P : as you might expect, more English words start with S than any other letter; based on the ENABLE word list, P is the second most common initial letter, followed by C
- B
- D
- K : the symbol K comes from
*kalium*, the Medieval Latin for*potash*, from which the name*potassium*was derived - X
- V
- Z
- Y
- G : a lowercase
*g*can be written in two different ways, and the more common version in typesetting (known as the “loop-tail*g*“) can be recognized but not written by most adults, as recounted on the D-Brief blog - L
- U : see this article from
*The Economist*, especially this image - S
- Q
- M

### Don’t Believe the HIPE

Let’s get this party started with a classic word puzzle.

What English word contains four consecutive letters that appear consecutively in the alphabet?

In *Mathematical Mind-Benders* (AK Peters, 2007), Peter Winkler describes how the puzzle above served as inspiration for a word game.

I and three other high-school juniors at a 1963 National Science Foundation summer program began to fire letter combinations at one another, asking for a word containing that combination… the most deadly combinations were three or four letters, as in GNT, PTC, THAC and HEMU. We named the game after one of our favorite combinations, HIPE.

This seemed like a good game to play with my sons. I explained the game, and then I gave them a simple example to be sure they understood.

ER

They quickly generated a long list of solutions, including:

- tERm
- obsERver
- fishERman
- buckminstERfullerene

Since that introduction a few weeks ago, the boys and I have played quite a few games. It’s a good activity to pass the time on a long car ride. The following are some of my favorites:

WKW

RTWH

RTHW

(these two are fun in tandem)HIPE

(the game’s namesake is a worthy adversary)TANTAN

The practice with my sons has made me a better-than-average HIPE player, so when I recently found myself needing to keep my sons busy while I prepared dinner, I offered the following challenge:

Create a HIPE for me that you think is difficult, and I’ll give you a nickel for every second it takes me to solve it.

Never one to shy away from a challenge, Eli attacked the problem with gusto. Fifteen minutes later, he announced, “Daddy, I have a HIPE for you,” and presented me with this:

RLF

That was three days ago. Sure, I could use More Words or some other website to find the answer, but that’s cheating. Winkler wrote, “Of course, you can find solutions for any of them easily on your computer… But I suggest trying out your brain first.”

The downside to relying on my brain? **This is gonna cost me a fortune.**

For your reading enjoyment, I’ve created the following HIPEs. They are roughly in order from easy to hard, and as a hint, I’ll tell you that there is a common theme among the words that I used to create them.

- MPL
- XPR
- YMM
- MSCR
- MPT
- ITESI
- NSV
- RIGON
- OEFF
- CTAH
- THME
- SJU
- TRAH (bonus points for finding more than one)

Winkler tells the story of how HIPE got him into Harvard. He wrote “The HIPE Story” as the essay on his admissions application, and four years later, he overheard a tutor who served on the admissions committee torturing a colleague with HIPEs and **calling them HIPEs**.

I can’t promise that HIPEs will get you into college, but hopefully you’ll have a little fun.

### A Cool Quick Trick for Pi Day

To some extent, I’m anti‑Pi Day. I think it has to do with the predictability of celebrations — everyone serves pie, does circle problems, and says things like, “I’m like π: irrational, but well-rounded!”

So, I was thinking that I would boycott Pi Day this year by not posting anything about the holiday on the MJ4MF blog. Then I discovered a cool trick. It was attributed to Martin Gardner on a web site, but I can’t verify the source. I think I’ve read every book by MG, and I’ve never seen it before.

Anyway, here’s the trick.

Write all 26 letters of the alphabet, but start with the letter J:

JKLMNOPQRSTUVWXYZABCDEFGHI

Then, remove all the letters that have vertical symmetry:

JKL N PQRS Z BCDEFG

Now, count the letters that remain in each subset: 3 1 4 1 6.

When I did this trick at a K‑12 math teachers’ conference recently, I wrote the numbers under each group. But I wasn’t sure that everyone would recognize the digits. So I drew an exaggerated decimal point between the 3 and 1, and I stated, “If you don’t know why this is relevant with Pi Day just around the corner, you’ve really missed the *point*.”