Math Links for Week Ending Jan. 29, 2016

In the last few weeks I have come across some great conversations on Twitter. This week was no different. In this case @MrOrr_Geek posts the kernel of an idea: given a quadratic, give two truths and a lie.

Here's a quadratic function. Give me 2 truths and 1 lie about its graph. #MTBoS #reviewQuestions #mathchat pic.twitter.com/Om3j9z5aV6

— Jon Orr (@MrOrr_geek) January 24, 2016

He gets some suggestions and then creates a post about this simple exam review strategy. Though this particular example is dealing with quadratics, you could easily see how any topic could be done this way. In fact, in the blog post he does it with a rational function and his grade 12 class (and really doesn't need to be limited to an exam review).
Curriculum Tags: MPM2D, MFM2P, MCR3U, MCF3M, MBF3C. MHF4U
http://mrorr-isageek.com/better-questions-two-truths-one-lie/

I have always liked doing this activity with my data management students where I asked them to go home and find two magazines then determine the total number pages, number of pages with ads on them and the cost. They all bring that data in and it builds a nice rich dataset. You can do one and two variable analysis with it. And thanks to Google Forms, collecting that data has become even easier. So there are well over 200 pieces of data in the set now.
Curriculum Tags: MDM4U
http://found-data.blogspot.ca/2016/01/magazines.html

Another nice review strategy from @MrOrr_Geek. Though this comes from his Advanced Functions class, it is another strategy that could be applied to just about anything (as long as answers come out to numbers). Put the kids in groups, give each group a set of problems then write the sum of each groups question on the board. If they get the same sum then they know they did their questions right, if not then they have to re-check (BTW, I love that kids are writing their solutions with dry erase markers on their desks).
Curriculum Tags: All
http://mrorr-isageek.com/sum-it-up/

When ever I used to teach combinatorics I wouldn't miss talking about lotteries and specifically those like the 6/49 or the Powerball. Invariably we would talk about being able to buy all the possible combinations and what that would take. It was pretty quickly determined that you would need a huge effort or at least some sort of automation (much like Lazlo had if you have ever seen the movie Real Genius). Well, as it turns out, somebody has actually done this. They filled out and played every combination. Listen to this Planet Money story to find out how.
Curriculum Tags: MDM4U
http://www.npr.org/sections/money/2016/01/13/462982983/10-11-51-52-62-18

Another recent story from Planet Money is about the fact that many psychological studies are actually not repeatable. When talking about data management we often talk about bias and this episode talks about how bias could be why some of these studies are not repeatable.
Curriculum Tags: MDM4U
http://www.npr.org/sections/money/2016/01/15/463237871/episode-677-the-experiment-experiment

I think @MaryBourassa has touched on an interesting point in a very short post she made recently:

"I don't know if it's just me, but I find it difficult at the end of the semester to give appropriate wait time when giving individual help. I will ask a question and want to jump in with the answer or will want to just tell them how to start a question rather than asking a question to get them to think about what they should be doing."

I think many of us became teachers because we like that warm feeling of imparting knowledge. Traditionally that has come in the form of us telling students about math rather then letting them struggle to get there but us telling students all the time is very passive for students. They need to be active learners in order for that information to stick. Let Mary know how you feel about this on her blog.
Curriculum Tags: All
http://marybourassa.blogspot.ca/2016/01/mpm2d-day-78.html?m=1

If you are talking about patterns then it is always neat when you can talk about an interesting pattern. In this case, take a whole number and follow the pattern: if it is an even number, n, then the next term is n/2 and if it is an odd number then the next term is 3n + 1. It is pretty simple but the interesting thing is that no matter what the starting point, it will always reach one. Thanks to Mark Esping for this one.
Curriculum Tags: Gr7, Gr8
https://www.youtube.com/watch?v=m4CjXk_b8zo

As it turns out there are many videos like this one, thanks to the iPhone. I like it because when are talking about combining functions in MHF4U I have always liked to show that sound waves were made from simpler sine waves. I would get an oscilloscope and wave generator from the science dept and show it. Now all I need is a phone and a guitar (or this video). Thanks to Mark Garant for this one
Curriculum Tags: MHF4U
https://www.youtube.com/watch?v=CyHjY5HB21g

Some good @Desmos videos on how to use the Teacher.Desmos.com site. Do you want to get started and aren't sure how? Start here
Curriculum Tags: All
https://www.youtube.com/watch?v=2KZ3MsZYuts&list=PLfM6zMGnbgOF9YIzu6VFtlYqk3SA2CbRm

It's always nice when you can bring data into the class that might be interesting to students. Here we have data to suggest that the number of words that Disney princesses have spoken has become less and less over time. Check the site out for a video and more data
Curriculum Tags: Gr7, Gr8, MDM4U
https://www.washingtonpost.com/news/wonk/wp/2016/01/25/researchers-have-discovered-a-major-problem-with-the-little-mermaid-and-other-disney-movies/

A recent theme of the MTBoS Blogging Initiative was "My Favourite". I like this simple way to pique student's interests to start this problem from @jgibson314.
Curriculum Tags: Gr7, Gr8, MFM1P
http://jgibson314.blogspot.ca/2016/01/my-favourite-problem.html

Do you want a fun way to look at order of operations? Try this limerick. Thanks to Michele Cooper for this one
Curriculum Tags: Gr7, Gr8
https://scontent-lga3-1.xx.fbcdn.net/hphotos-xfp1/v/t1.0-9/12552755_1079701435415225_4583467602856992172_n.jpg?oh=f6b4b1160150a11ad548f004709734ec&oe=5725D60C