Number Devil Activities: The Third Night

Appearing the Third Night, the Number Devil takes Robert on a lesson in "Prima Donnas" in other words... Prime Numbers.  Since our dreams aren't filled with great mathematical adventures from the Number Devil, we'll have to settle for making great mathematical adventures during our math lessons.  Prime numbers are intriguing and mysterious.  No pattern to prime numbers has ever been found.  Twenty-five percent of the numbers between 1 and 100 are primes, but fewer than 4 percent of numbers up to a trillion are prime.  (Aristotle Leads the Way)

The Number Devil introduces Robert to the Sieve of Eratosthenes.  Around 200 b.c. the great mathematician Eratosthenes developed an algorithim to find prime numbers.  This algorithim continues to be used today for prime numbers less than ten million.  The process the Number Devil takes Robert through- crossing off mulitiples of 2, then 3, then 5 is The Sieve of Eratosthenes.  Check out the Sieve of Eratosthenes Wikipedia entry for a clear explanation of the algorithim.

Activity One:

Practice the Sieve of Eratosthenes.  Print off this chart and find all the prime numbers up to 100.  It will be a helpful tool to have as a reference and for further prime number activities.

Activity Two:

Go on a Prime Number Scavenger Hunt.

Activity Three:

Make Prime Number Trail Mix.  Before eating the mix, experiment with the Number Devil's trick...

"Take any even number- anyone at all, so long as it's larger than two- and find two prima donnas that add up to it." (pg. 62)

"It works with odd as well as even numbers.  Think of a number, any number, so long as it's bigger than five... You can find the prima donna numbers that add up to them too, only instead of two you'll need three." (pg. 64)

Use your trail mix as manipulatives to help solve the problems.

Activity Four:

Prime for Life Challenge

Activity Five:

Play Hong Kong Prime Number Arcade

These activities can be used as stand alone projects for any lesson on prime numbers and are especially fun to do along with studying The Number Devil.

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