π ≈ 3.141592653589793238462643383279502884197169399375105820974944592307816406286208998628034825342… click for the first million digits!

More books…

Alternative timeline of the history of mathematics

Alternative timeline of math history… 15-ft-long wall poster

Stairs investigation…

Tees + mugs…

The PiFactory blog Assessment Books Tees + mugs
Learning targets
2,600+ questions linked to learning targets
Coming... searchable online textbook

Assessment

For a full discussion about the appallingly negative impact of most assessment — alpha-numeric grades, tests, graded homework — on western education + loads of links to the research go to The PiFactory Blog

Click for a look at what an alternative grade-book could look like.

Instead of mathematically-meaningless percentages and alpha-numeric grades, assessment could be based on descriptions of achievement:

Got it

Getting it

Starting

Stuck

Grades

How students can assess themselves

For some thoughts on homework + links to the research that exposes the myth that it is vital to our children's education go to Why I no longer set homework and some thoughts on homework for parents.

For some the research on the negative effects of testing go to the classic Testing, Motivation and Learning from the UK's Assessment Reform Group. For a review and other links on testing see Research gives testing an F plus for a review of the latest pamphlet from Paul Black and friends, go to Working inside the black box

Language Barrier with Orange, 2005, by Mary Henry
MARY HENRY, whose abstract art is a particular delight for lovers of geometry, has died aged 96.
An exhibition of her work can be seen at PDX Contemporary Art, 925 NW Flanders, Portland, OR 97209 until the end of May.

New biggest prime found


The biggest prime number yet has been found with some 12,978,189 digits. It would fill nearly 20 paperbacks if printed out.

It's also the 45th known Mersenne prime, a rare sort of prime written as a power of 2 subtract 1: 243,112,609 − 1.

That's 2 multiplied by itself 43,112,609 times and then subtract 1.

A prime number can only be divided by the number 1 and itself — it has only two factors.

The discovery by the UCLA math department qualified for a $100,000 award for the first prime of more than 10 million digits.

It was discovered using software from the Greater Internet Mersenne Prime Search — GIMPS — that allows anyone with a PC or laptop to help search for the next largest prime.

This new big prime was discovered in August 2008. Just two weeks later another — smaller — 46th Mersenne prime was discovered near Cologne, Germany: 2 37,156,667 − 1. It has a mere 11,185,272 digits.

Mersenne primes were first discovered by the French monk and mathematician Marin Mersenne more than 300 years ago.

Searching for primes was the sort of thing maths people did for fun, they still do. But now super-big primes are vital in internet and banking security as well as writing ultra-secret codes.

Mathematicians know there are an infinite number of primes. They think there an infinite number of Mersenne primes, but the conjecture has yet to be proved.
Copyright David Whitfield, The PiFactory, 2002-2010 + Email: davidwhitfield AT pifactory.net. Designed + produced by David Whitfield