This Week at the Global Math Department

Edited By Nate Goza  @thegozaway
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Online Professional Development Sessions

Learning Math in a Digital Environment

Presented by Cal Armstrong

Learning mathematics for students requires a lot of diverse materials : notes, pictures, graphs, interactives, worksheets, equations, feedback, review materials. How do they have a workflow that works for all these different media; how do they collect, manage and cope while at the same time meeting with accessibility & language needs? And how do teachers manage to deal with all of that along with the need to do assessments, give feedback, observe, reflect and just “teach”? We’ll go through how #digitalink & OneNote have made all of this manageable and has in fact increased learning time in the classroom while adapting to the desire to engage in discussions, #vnps, student voice/choice, visualization and other common practices of the modern classroom.

To join us at 9:00 PM EST for this webinar click here!

GMD is Looking for Presenters!

Do you know someone who you think should lead a GMD Webinar?

Did you see something amazing at a recent conference that needs to be shared?

At Global Math we are proud of our Webinars!  We appreciate all of our presenters and look forward to bringing you the best “PD Iin Your Pajamas” on the internet.  We’re always on the lookout for fresh faces and new ideas.

Please use this recommendation form to let us know who/what should be shared next!  We will take your recommendations and reach out to try to make it happen!

In next week’s webinar Frank Wapole and Evan Borkowski will be here to challenge us to rethink Math homework.  You can get more info on the session and register here.

You can always check out past Global Math Department webinars. Click here for the archives or get the webinars in podcast form!

From the World of Math Ed…

Much Ado About Taxes

In recent weeks, the media has been abuzz with talk of tax rates. Most visible has been the headlines surrounding Rep. Alexandria Ocasio-Cortez’s talk of increasing the top marginal tax rate to 70%. This news has sparked much debate from all sides of the political spectrum. But regardless of your political beliefs, it’s been illuminating to witness the conversations and, in some cases, misunderstandings surrounding the system of income taxation in the United States.

So what’s this got to do with the math ed community? Well, if there was ever a moment for us to shine, this is it!

First up, Dan Meyer has written a blog post with some ideas and resources for helping our students understand marginal taxation. Dan also mentions an amazing collaboration between the New York Times Learning Network and the American Statistical Association called What’s Going on in This Graph? and, even better, Desmos teacher activities that enable teachers to have these conversations through the Desmos platform.

Second, Ben Orlin includes talk of taxes in his critically acclaimed book Math with Bad Drawings. As Ben mentioned on Twitter, the chapter stemmed from a “make your own income tax system” project that he used to give to his precalculus students. He also points out that, interestingly, marginal tax rates are a piecewise-constant function of income while tax paid is a continuous, piecewise linear function.
Third, @voxdotcom came out with a fairly well-made video explaining how tax brackets work. It may be interesting to connect the visual representation of tax brackets as “pockets” with the algebraic concept and notation of piecewise functions. I was particularly impressed by the fact that the video also mentions deductions, a concept often overlooked when people talk about income taxes in the United States.
Ultimately, what’s at stake is not just our students’ mechanical understanding of marginal tax rates. Rather, this is about the aspect of our work as teachers that involves helping our students develop mathematical literacy. In Paulo Freire’s words, before we teach our children to read and write, we must teach them to “read and write the world.” Beyond focusing on high test scores and college acceptances, we must help our students approach the complexities of the world with an array of intellectual tools. We must also help them develop the social and political sensitivities to use those tools with wisdom, agency, and compassion.
Written by Melvin Peralta (@melvinmperalta)
Black History Month, is a time to celebrate and amplify Black voices, stories, shed light on injustices, and teach.  Look at this article Teaching Black History Month from Tolerance.Org for inspiration and lessons.

Click on the image below for some people to follow on Twitter:

Here are some books to read by Black authors;

  1. White Rage by Carol Anderson (Thanks again to Val Brown for leading rich discussions on #ClearTheAir.)
  2. PUSHOUT by Monique W Morris EdD

See Morris’ Retweet with 100 books by Black women authors (image is link):

Finally, if you are teaching about Math History check out Mathematically Gifted and Black.

Contributions compiled by Diana McClean (@teachMcClean)

Number and Space are Inextricably Connected

Try this: close your eyes, and think of an open number line. You just need to picture a line, no intervals marked, just a certain amount of space. That line will have a length, although it is difficult to tell how long your mental image of this line is.

We know this line could stretch from some starting point, to infinity, or rather to some infinite length, which we cannot measure. We could mark an infinite number of points on this line, and actually, we could mark two different types of infinity on this line: counting numbers, and real numbers, which are demonstrably at a higher level on the “tower of infinity”.

But we are getting ahead of ourselves.

Close your eyes, and picture a line of length 10 units. Hold up your hands however long you think that line should be.

Now open them. Where are your hands?

Try the same exercise for 20. Where are your hands?

Here is an interesting tweet thread about some experiences I had working on number lines with grade ones. My colleague asked them to visualize 20.

Consider trying this with your students. Whether “shoulder width” is a preferred human length for number lines is an open question. Perhaps “body scale” is most relatble to us humans.

If you want to blow their minds, ask them to draw an open line of some length, mark 0 and one million as the ends. Where is 1000? Now do the same for one billion. Where is one million?

Space and number are mysteriously connected. As I understand the research, we know they are connected, there is no doubt, we just don’t really know how.

Work is being done in this area. See the pre-print in this tweet below, and consider reading it. Zach Hawes and Daniel Ansari are working on what happens in the brain to connect space and number. Basically, there is an emerging body of evidence that spatial reasoning and thinking about numbers are connected, as shown by fMRI mapping of the regions of the brain responsible for each.

Research continues, seeking to find this “missing link”. In the meantime, an open number line is a tool “with legs” in grade 1-12 education. (Typically, Kindergarten students aren’t quite ready to go past concrete counting objects, ten frames, and on to the number line).

Written by Matthew Oldridge (@MatthewOldridge)

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