” ‘Use logic in math’ is my motto.” — Sophia S (October 31, 2010)
That, and persistent, hard work, are why she gets mostly As. I love that quote.
July 25, 2011
July 20, 2011
July 18, 2011
Pythagorean Triples
Geometry For Enjoyment and Challenge, by Rhoad, Milauskas and Whipple (publishers McDougal Littell/Houghton Mifflin), has some rules for generating Pythagorean triples (see also Mathworld.Wolfram.com) on p. 403:
Rule of Pythagoras: for n an odd number, the triple will be n, (n^2 – 1)/2, (n^2 + 1)/2;
Rule of Plato: for n an even number, the triple will be n, n^2/4 – 1, n^2/4 + 1;
Rule of Euclid: for m and n both even or both odd, the triple will be (m – n)/2, sqrt(mn), (m + n)/;
Rule of Maseres: for m and n any two integers, the triple will be m^2 – n^2, 2mn, m^2 + n^2.
Nice!
July 12, 2011
The Importance of Mathematics: An Example
The Lake Peigneur salt dome drilling disaster, which you can read about on Wikipedia and see on YouTube (and on EducatedEarth.com), demonstrates the importance and truth of the dictum “measure twice before you cut once.”
July 3, 2011
Mental Math
On YouTube, Total Breeze has some good videos on mental math: addition, subtraction, multiplication, division, and square rooting. Worth watching.
June 29, 2011
Postprandial Math Joke
Q: Why do mathematicians, after a dinner at a Chinese restaurant, always insist on taking the leftovers home?
(more…)
June 28, 2011
Beach Math Joke
Q: Why do you rarely find mathematicians spending time at the beach?
June 21, 2011
Math Joke
Q: What do you get if you divide the circumference of a jack-o-lantern by its diameter?
June 16, 2011
Mistakes in Modern (Public) Education
In “Singapore Math Tough to Adopt” (Education Week, Teaching Now Blog, June 9, 2011), Liana Heitin writes:
And Singapore Math requires extensive (and costly) professional development, and “a depth of understanding most U.S. elementary teachers don’t acquire in their math training,” according to [Bill Turque at The Washington Post].
And in “NAEP History Repeats Itself: Flat Scores Except 8th Grade” (Education Week, Education Week Spotlight, June 14, 2011), Erik W. Robelen writes:
The nation’s 8th graders posted gains in American history achievement compared with four years ago, new data show, but only a small minority, 17 percent, were rated “proficient” or higher in the subject.
…
Meanwhile, at the 4th and 12th grades, history essentially repeated itself, with no statistically significant changes since 2006. Just 12 percent of seniors and 20 percent of 4th graders scored at least proficient.
…
“It should concern us all that 12th graders’ knowledge of history has barely changed since 2001,” [said Diane Ravitch, a research professor at New York University]. “All of these students will be voters in a year, and almost 40 percent were already eligible to vote when they took the assessment. … They should be well informed and capable of weighing the contending claims of candidates, especially when the candidates rest their arguments on historical precedent.”
We need to privatize education, and make it rational and objective. These things would help teachers and students alike, in all sorts of ways. Both teachers and students deserve better.
May 12, 2011
Pendulum Waves
Someone posted a video of pendulum waves on YouTube. Absolutely amazing. Beautiful.
