Math Links for Week Ending Mar. 18th, 2016

A few posts Pi Day links to put in your repertoire for next year. The first from @rjallen on some things you may not know about Pi. I love examples of connections to Pi that don't seem to be related to the circle like the connection to gravity. And I love the expansions that approximate Pi. In this case he shows simple code that generates the values right there for you.
Curriculum Tags: All
http://www.wired.com/2016/03/six-things-probably-didnt-know-pi/

I love the animated gif that @MrOrr_Geek uses to start his discovery lesson on the sum of angles in a polygon. Then he connects it quite nicely to linear relations. There is a nice mix of hands on and technology here. In the past I have used this GSP sketch to do it for interior angles (and this one for exterior angles) and although there are some nice dynamic visuals, I think I might use this new investigation and then maybe the GSP as a consolidation piece.
Curriculum Tags: MPM1D, MFM1P
http://mrorr-isageek.com/from-circles-to-polygons/


A couple of new websketches from @dpscher. The first is a nice dynamic visualization of multiplying fractions. It works well with the checking fairly accurate about the size of the shaded rectangles as well as accepting both reduced and unreduced answers.
Curriculum Tags: Gr8
http://blog.keycurriculum.com/understanding-fraction-multiplication-2/

The second is a websketch that let's students explore tessellations. Kids can really free form construct with many different regular shapes. Take a look (click on the first image to actually try it out. Years ago I made my own GSP tessellation sketch, you can check that out here.
Curriculum Tags: Gr7, Gr8
http://blog.keycurriculum.com/exploring-tessellations-with-web-sketchpad/


Don't know what it means to ask a question with a low floor and high ceiling? Check this post out by @dsladkey to see how he explores expanding binomials by starting with a image from Visualpatterns.org and then it goes from there.
Curriculum Tags: MPM2D, MFM2P
http://teachhighschoolmath.blogspot.com/2016/02/taking-20-minutes-for-one-problem-look.html

Why are you using that problem? That is what @robertkaplinsky is asking. That is, why did you use that particular question in your math class? He goes through three reasons he believes you should be using any particular problem: Introducing a new concept, for productive struggle, or for problem completion. Get the full info at the link below
Curriculum Tags: All
http://robertkaplinsky.com/why-are-you-using-that-problem/

I wonder how many articles on Pi @StevenStrogatz has written? Here's the latest on why Pi maters.
Curriculum Tags: All

http://www.newyorker.com/tech/elements/pi-day-why-pi-matters




Is it possible that prime numbers do not appear randomly. There seems to be some evidence that, in fact, they aren't random in placement. Find out more here.
Curriculum Tags: All
https://www.newscientist.com/article/2080613-mathematicians-shocked-to-find-pattern-in-random-prime-numbers/

Vi Hart's latest Pi Day rant came out on Monday and her beef this year is that the date 3/14/16 is actually a better approximation of Pi than last year's 3/14/15 due to the fact that 3.14159 rounded to four decimals is closer to the value of Pi then when it is truncated (like last year's date). However, the difference is that last year you could incorporate the time to get 6 more decimals. I can over look that cuz I just love Vi's posts.
Curriculum Tags: All
https://www.youtube.com/watch?v=vydPOjRVcSg

For Pi Day @standupmaths calculated Pi by hand using an infinite series. He does this explicitly so it's an 18 min long video. It's good for showing how a series works and also for the idea of how some series converge (and how this is a bad series to calculate Pi).
Curriculum Tags: MCR3U, MHF4U, MCV4U
https://www.youtube.com/watch?v=HrRMnzANHHs

It's March break and we are in Florida for the week. The house we are staying at (like just about every other rental house) has this huge screened in enclosure for the pool. Definitely geometry here.
Curriculum Tags: Gr7, Gr8, MPM1D, MFM1P
https://twitter.com/davidpetro314/status/709437468836294656

Who says #geometry doesn't show up in real life #mathchat pic.twitter.com/me4VcWgIco

— David Petro (@davidpetro314) March 14, 2016