February Update: Blog Evolution Meme

This picture is my all-time favorite LolCat, because it is so true to life. Every time I sit down to read a book or grade homework, one of our kittens plops herself on top of it and starts chewing the corners.

Blog Evolution Meme

Jonathan tagged me for the blog evolution meme, in which one chooses five posts that represent the development of one’s blog. Hmmm…

Remember the Math Adventurer’s Rule: Figure it out for yourself! Whenever I give a problem in an Alexandria Jones story, I will try to post the answer (relatively) soon afterward. But don’t peek! If I tell you the answer, you miss out on the fun of solving the puzzle. So if you haven’t worked these problems yet, go back to the original post. Figure them out for yourself — and then check the answers just to prove that you got them right.

The Secret of Egyptian Fractions

Alex made a poster of Egyptian-style fractions, from 1/2 to 9/10. Many of the fractions were easy. She knew that…

$\frac{5}{10} = \frac{4}{8} = \frac{3}{6} = \frac{2}{4} = \frac{1}{2}$

Therefore, as soon as she figured out one fraction, she had the answer to all of its equivalents.

She had the most trouble with the 7ths and 9ths. She tried converting these to other fractions that were easier to work with. For example, 28 has more factors than 7, making 28ths easier to break up into other fractions with one in the numerator.

Math Links for Fun and Charity

Photo by James Cridland.

Aargh! My computer died again. So I borrowed my daughter’s laptop and ran off to the coffee shop to write blog articles — and discovered that all the outlets on the wall here are fake. Why would they do that? Anyway, before the laptop battery dies, I want to share a couple of math links with you…

Way To Go, Boys!

Congratulations, math team! All your hard work paid off, and I hope you enjoyed yourselves thoroughly. Of course, as C. S. Lewis wrote:

…if you do one good deed, your reward usually is to be set to do another and harder and better one.

Now it’s time to practice for the state level in March. You can find practice problems online at:

Preparation Drills for MATHCOUNTS
or
The “Go Figure!” math challenge
[ACK! MathCounts has re-written their website. The old link is no longer any good, but I haven’t yet found the new location for this game.]

And give the new interactive Countdown Round game a try:

AoPS For The Win!

500 (?) and Counting

Photo by rileyroxx.

Could this be my 500th post? That doesn’t seem possible, even counting all those half-finished-and-then-deleted drafts. Well, at least it is my 500th something, according to the WordPress.com dashboard. And surely a 500th anything is worth a small celebration, right?

Maybe my students aren’t so bad, after all…

It has been awhile since I posted a link to Rudbeckia Hirta’s Learning Curves blog. Here are a few of her students’ recent bloopers:

The Secret of Egyptian Fractions

Photo from Library of Congress via pingnews.

Archaeology professor Dr. Fibonacci Jones came home from a long day of lecturing and office work. Stepping inside the front door, he held up a shiny silver disk.

“Ta-da!” he said.

“All right!” said his daughter Alexandria. “The photos are here.”

They had to chase Alex’s brother Leon off the computer so they could view the images on the CD, but that wasn’t hard. He wanted to see the artifacts, too. Alex recognized several of the items they had dug up from the Egyptian scribe’s burial plot: the wooden palette, some clay pots, and of course the embalmed body.

Then came several close-up pictures of writing on papyrus.

Photo from MathsNet.net.

How to Write Egyptian Fractions

“I remember how to read the Egyptian numbers,” Alex said, “but what are these marks above them?”

Dr. Jones nodded. “I thought you would catch that. Those are fractions. The scribe places an open mouth, which is the hieroglyph ‘r’, over a number to make its reciprocal.”

“I know that word,” Leon said. “It means one over the number. Like, the reciprocal of 12 is 1/12, right?”

“That is right. 1/12 would be written as…”

The Rest of the Story

As I transcribed this article from my old math newsletter, I realized that it would require more graphics than I was willing to construct. LaTex does not handle Egyptian hieroglyphs — or at least, I don’t know how to make it do so. Instead, I decided to scan the newsletter pages and give them to you as a pdf file: