I tend to use this instead of sieve method.
Have got several classes to think about primitives
Your website/this page is very useful
Thank you for a beautiful applet! We used this in a Math Club today, together with the poster “You can count on monsters” from here: http://www.math.brown.edu/~res/PosterPrimes/post5.png Kids and parents were making up their own ways to “tally” numbers. Erin noticed that there is no consistent rule to how groups are formed. For example:
– 6 is “three groups of twos” but 12 is “two groups of two groups of threes”
14 is “seven groups of twos” but 21 is “three groups of seven”
We were wondering if there is some hidden logic and beauty in this choices – or are they random to show the variety of possibilities?
Thanks for your feedback. I’m really glad that this resource is still being used to teach maths!
The ordering of the primitives is random, but if you click on the bar on the right (that shows a 2 and a 3 in circles for example) and drag them into a different order you can make “three groups of two” into “two groups of three”. I made the application very quickly for my own class, and never really finished it, so some of its features are a little bit hidden.
Thank you for showing me the monsters poster. I had no idea it existed; it is lovely to see someone has a similar thought process to me!
Alec, how cool! I am sending this on to the Club members. Maybe you can just draw a little “hand” icon next to numbers, or some other symbol for “drag me.” I really like this feature.
The poster’s author, Richard Evan Shwartz, just published a book based on it. I sent him your applet’s link yesterday, and he did not know about it – he said it’s really neat.
I am working on a similar idea from a different angle, still: finding “essential multiples” in nature or culture. Some examples are here: http://www.naturalmath.com/multpics/index.php However, this software turned out to be so clanky I disconnected it from the front page of the site. I plan to continue this using a better tool, like Prezi, LiveBinders or Wallwisher. Thank you for the inspiration!
Thank you for a beautiful applet! We used this in a Math Club today, together with the poster “You can count on monsters” from here: http://www.math.brown.edu/~res/PosterPrimes/pos… Kids and parents were making up their own ways to “tally” numbers. Erin noticed that there is no consistent rule to how groups are formed. For example:
– 6 is “three groups of twos” but 12 is “two groups of two groups of threes”14 is “seven groups of twos” but 21 is “three groups of seven”
Thanks for your feedback. I'm really glad that this resource is still being used to teach maths!
The poster's author, Richard Evans Shwartz, just published a book based on it. I sent him your applet's link yesterday, and he did not know about it – he said it's really neat.
what the hell is this meant to be
ha ha ha ha!
hi poopa wats going on bro
Such a cute way to get the concept of prime numbers across. My own kid hasn’t yet started multiplication, so I am keeping my fingers crossed that this will still be there a year or two down the line when I need it!
I can assure you this site isn’t going anywhere. I stopped teaching in 2006, and it’s still here =)
Muito bos esta ferramenta. Ela é muito útil para trabalhar além de números primos, alguns agrupmanetos importantes.
It’s not working!
I enjoyed the site and want you to dem well with students!!!
Really beautiful. I wish I could buy a version to use offline as we often have no internet available in community ed.
Hi Pittske! Follow this link and use File/Save-As and you should be able to use the file offline. All the best! http://bit.ly/18dxM5H
That’s really kind of you. I tried but I can’t save – it also jumps around in a crazy way.
Sorry that didn’t work. Perhaps you can ask someone with a bit more technical knowledge? The link I sent you is for a Flash SWF file, which you should be able to save and run directly on a Flash Standalone Player. That should be all you need to get this running on a local machine. Good luck!
This applet is clever and wonderful. What it needs is faster, more efficient ways to jump ahead to much larger numbers. There is no quick, efficient way to skip ahead to ten thousand, or one billion, or ten factorial, or the fiftieth Fibonacci number. One should never have to click the same button twenty or more times in a row.
You can click on the displayed number and type in a new number to calculate, though you should be aware of two things: firstly, this (probably) only works in not-fullscreen mode, due to a security restriction that existed in the Flash player at the time I wrote it. Secondly, really big numbers like the ones you mentioned will almost certainly crash your browser. At 10! or 1,000,000,000 or some other big number it is going to try to calculate the prime factors of that number, which will take a while. Then, even worse, it’s going to try to draw a dot for each of unit in those numbers, and arrange them appropriately. All this runs on your computer, and will consume a vast amount of memory and processing power. However, before it melts your machine, your browser will detect that the Flash player is trying to consume an inappropriate amount of memory, and will crash. Good luck pushing it as far as you can!
it is great
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