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IntMath Newsletter: Numberphile, a murderous math teacher, resources

By Murray Bourne, 10 Nov 2011

10 Nov 2011

In this Newsletter:

1. YouTube to pay for videos: Numberphile
2. The murderous math teacher of S-21
3. Geometry in Art - free PDF book
4. How to visually find the greatest common divisor
5. Math polls
6. Resource: nrich
7. Friday math movie: Pipe Dream by Animusic
8. Final thought - showing up

0. Latest IntMath feedback

I love getting feedback from readers. It's great to know how IntMath is helping people. This came from Jason in the USA this week:

IntMath has been a lifesaver for me in Calculus for Engineers. You alone have taught me far more than my "prestigious" college professor has taught me all year. Your site is the best resource for math on the web, and you address all topics that other sites are afraid to address. The lessons are the perfect length and very easy to follow. I wish I could take my tuition money back from my university and give it you!

Good luck with your studies and thanks for the kind words, Jason!

1. YouTube to pay for videos: Numberphile

YouTube has funded numberphile

Tomorrow, 11/11/11, YouTube will launch numberphile, a brand new channel dedicated entirely to numbers. YouTube is investing $100m in this, and rather than getting videos made by users as usual, the money will go to big-name media companies and personalities. Could be well worth watching! YouTube is owned by Google, and there are many math geeks in Google!

(The suffix "phile" means "lover of". So a numberphile is someone who loves numbers.)

Go to: numberphile

2. The murderous math teacher of S-21

The murderous math teacher of S-21

In a chaotic situation, a math teacher begins a murderous rampage of torture.

This true story is quite disturbing. I wrote it after a recent visit to Cambodia.

The murderous math teacher of S-21

3. Geometry in Art - free PDF book

Geometry in Art - free book

Unfortunately, this PDF has since disappeared! Sorry about that.

Here's a free offering that shows how artists have used spirals, solids, the Golden Ratio, and religious symbols as art throughout the ages.

The book is by Portuguese professor, Marcelo R. M. Crespo da Silva

Geometry in Art - free PDF book

4. How to visually find the greatest common divisor

GCD using GeoGebra

The Greatest Common Divisor (GCD) is the largest number that divides into any 2 given numbers. For example, the GCD of 8 and 12 is 4.

Here's a neat GeoGebra applet that helps us to find the GCD of 2 numbers, visually. (Please be patient while it loads.)

Can you figure out why it works?

Find the Greatest Common Divisor - using GeoGebra

5. Math polls

What is your favorite math activity?

The latest poll asked readers about their favorite math activities. It is surprising (to me) how many chose "algebra". Really? And for "none of these", does it mean they enjoy "no math activity"?

Doing algebra: 38%

None of these: 25%

Calculator: 16%

Doing geometry: 11%

Drawing graphs: 10%

Total votes: 2700

Poll date: Oct 2011

Current poll: The current poll asks readers about their calculator use. You can answer on any page in

6. Resource: nrich

Suitable for: Students and teachers

The NRICH Project aims to enrich the mathematical experiences of all learners.

On the nrich website you'll find thousands of free mathematics enrichment materials (problems, articles and games). All the resources are designed to develop subject knowledge, problem-solving and mathematical thinking skills.

Here are this month's problems, appropriate for IntMath readers:

Monthly problems for age 16 and above

Students can send in their solutions - the better ones get published! This is great for developing your problem-solving skills.

You can also see how math is used in the real world, like in biology, chemistry, and engineering.

There's plenty of support for teachers on nrich, too. See

nrich Curriculum

7. Friday math movie: Pipe Dream by Animusic


Here are 2 clever videos involving music and mechanics.

Friday math movie: Pipe Dream by Animusic

8. Final thought - showing up

Here's a good one from Dianne Houston, American director and screenwriter, who worked on NYPD Blue and City of Angels.

This could apply to success in math, too!

Only some people get what they want. Those are the people who show up to get it. [Dianne Houston]

Until next time, enjoy whatever you learn.

See the 5 Comments below.

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