## Posts tagged ‘clock’

### What Time Is It?

Here’s a math puzzle that is rather easy. Or is it?

You look in a mirror and see the reflection of a clock. In the reflection, the clock appears to show a time of 11:51. What is the real time?

Before I share the solution, how ’bout some clock jokes?

A hungry clock goes back four seconds.

I spent 35 minutes fixing a broken clock yesterday.
At least, I think it was 35 minutes…

What’s the difference between a man and a broken clock?
At least a broken clock is right twice a day.

It took me four hours to eat a dozen clocks.
It was very time consuming.

My clock stopped at 8:23 a.m. I’m going to have a day of morning.

Puzzle Solution

The puzzle above is based on a math trivia question I found at Trivia Cafe.

The answer could be 12:09, if the reflection in the mirror looks like this…

Then again, the answer could be 12:11, if the reflection in the mirror looks like this…

And of course, there are all the silly possibilities — for instance, if the clock is broken, it doesn’t matter what time shows in the reflection, regardless if it’s analog or digital.

### Humorous Math Poem Contest Winner

Winner will be announced below; but first, I’ve got to say this:

May the Fourth be with you.

(Hee-hee.)

Congratulations to Lucie, a student in Russ Holstein’s class. She was one of 36 entrants in the Humorous Math Poem contest, and her name was randomly selected to receive a signed copy of Math Jokes 4 Mathy Folks. Lucie’s entry was a haiku:

Don’t be dramatic;
It is just mathematics.
Easy: 1, 2, 3.

[Editor’s Note: The middle line was changed from, “It’s just…,” to, “It is just…,” to give it the requisite seven syllables.]

Other noteworthy entries were the following:

Dear Math,
I’m sick and tired of finding your x.
Just accept the fact that she is gone…
Move on, dude!
by Susanne

3.14159
Oh, these numbers make me whine!
2653589
7932384
I am really doing poor.
62643383279
If I learn this, will I shine?
3.14159
by Angela

Dear Aunt Sally,
For not following the rules;
I don’t have the right tools.
from wawrorl

I have a really geeky clock;
It has a special chime:
At 2, 3, 5, 7 and 11 o’clock,
It shouts out, “It’s prime time!”
by Chris

And my favorite, which seems to be a commentary on standardized testing…

Today we had a test, it was mathematical.
Which is very tragical.
And wasn’t all that fantastical.
I rather it be biographical.
Does it come from the capitol?
by Marie

Thanks to the folks at Thinkfinity for promoting this contest. All of the entries can be read in the Thinkfinity Community.

### Holiday Gifts to Avoid for the Math Geek on Your List

There are lots of lists with suggestions for what to buy a math geek. Don’t believe me? Just do a Google search for “gifts for math geeks.”

As a public service, I’m providing a list of gifts that no one, under any circumstances, should purchase for a math geek. If you’re not a mathy person, take note. Every item on this list will only bring disappointment to the mathy people in your life. If you are a mathy person, print this list, and tuck it into your mom’s purse or leave it on your sweetie’s pillow.

Math Wall Clock

I’ve railed against this one before, and for good reason. Absolutely the worst math gift EVER. The expression for nine is 3(π – .14). Apparently the designer of this clock face isn’t aware that π has a non-terminating decimal representation. And the expression for seven is 52 – x2 + x = 10, which has two solutions, 7 and -6. Let’s hope folks don’t start making dinner reservations for “negative six o’clock.” Sheesh.

Acme’s Klein Bottle Wine Bottle

You can take my word that this is a bad gift, or you can listen to the designer. The manufacturer describes it by saying, “As impractical as it is elegant.” Fact. The description is a litany of flaws: “Wine is trying to go down while the air is trying to go up the spout. Result is slow filling. Pouring wine out is equally frustrating.” And, “Not only are these difficult to fill and empty, but cleaning them is a real challenge.” And the piece de la resistance, “They’re easy to tip over, especially when empty.” On the flip side, their web site includes this gem, too: “Now with a LIFETIME GUARANTEE — you will live your entire life, or your money back.”

A better yet equally geeky option is the Klein Bottle Opener, which is practical if you’d like to use a non-orientable manifold to get the liquid out of a boundaryless compact two-manifold homeomorphic to the sphere. Unlike the Acme Klein Bottle, this tool works very well, and you look super cool using it. (Be careful; there are cheaper versions of this item that are only decorative. They won’t open bottles.)

xkcd: volume 0

Okay, sure, this hard-copy volume has “a lot of doodles, notes, and puzzles in the margins,” but, really, you’re paying for a bunch of comics that are available for free at xkcd. What’s more, the math geek on your list has already read all of these comics! (If not, then she isn’t a true math geek. Please call 1-877-NOT-GEEK, and we’ll revoke her license immediately.)

Want a book your math geek will really love? Might I recommend Math Jokes 4 Mathy Folks? (Okay, that was even too shameless for me.)

Need a synonym for geeky? How about dorky, nerdy, dweeby, techy, or studious? Want an antonym for geeky? Try stylish.

Math geeks don’t want silver cuff links. More importantly, they don’t need them. Honestly, what would they wear them with? Plaid flannel shirts don’t have cuff link holes. And for \$195, do you really want to buy something that will collect dust in his dresser drawer?

### Math Clocks

Jiminy. The folks at Clock Zone make a math class wall clock — and I would like to be the first to publicly chastise buy.com, amazon, and anyone else who is selling it. It contains at least two mathematical errors:

SPOILER ALERT: In my rant below, I identify the errors in the clock. If you’d like to identify them for yourself, don’t read any further.

I say “at least” two errors because there may be more. The obvious errors are for 9 (the expression assumes that the exact value of π is equal to the common approximation 3.14) and for 7 (because the equation is quadratic, x = 7 is only one of the answers; the other possible answer is x = ‑6).

More generally, I have an issue with any of the algebraic equations that are meant to represent integers. For instance, the equation 50/2 = 100/x has solution x = 4, but I believe that it is incorrect to say that the equation itself is equal to 4. So perhaps the clock has four errors, if you consider the algebraic equations for 4 and 10 to be erroneous, as I do.

This clock is meant to be a math joke. Edward de Bono in The Mechanism of the Mind (1969) suggested that when a familiar connection (such as seeing the numerals 1‑12 on a clock) is disrupted, laughter occurs as a new connection (seeing mathematical expressions instead of numerals) is made. Sadly, math jokes are supposed to make you laugh… yet this clock makes me want to cry.

To ease the pain, I did a little research and uncovered several clocks of famous mathematicians. I present them here for your enjoyment.

Leonardo da Pisa:

Kenneth Appel:

Rene Descartes:

Karl Friedrich Gauss:

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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