This past summer a conversation almost didn't take place. The two main reasons why it almost didn't take place were 1) it was on Facebook, and 2) it was going to be about police officers shooting and killing black people.
I'm not generally a fan of talking about politics on Facebook. It's not a great medium for exploring subtlety and nuance, and many people are really more interested in ranting than engaging in anything like a conversation. So when one of my Facebook friends posted this, I was tempted to ignore it, like I ignore a lot of things that are posted on Facebook.
I told myself that posting a response wouldn't change anyone's mind, that nobody's interested in engaging in any serious discussion on Facebook, and that most likely I'd just get some ugly comments directed at me, so what was the point? Ultimately, however, I decided that I did want to post a response, and it wasn't because I was dying to get into a discussion on whether the most recent shooting death of a black man at the hands of a police officer was justified. It was because my friend who posted this was making an argument based on flawed mathematical reasoning.
If you want to disagree with me about some political topic, I'm okay with that. But to get the math wrong? That I won't stand for.
So I posted this:
It turned out that not only did my response kick off a fascinating, and mostly civil, discussion, but I ended up turning it into a lesson in one of my math classes. (If you're interested, the entire discussion is in this set of powerpoint slides, and here's an accompanying writing activity I asked my students to complete.)
I liked this activity for several reasons:
- It connects math to an important current topic in an authentic way.
- There's an immediate "that can't be right" reaction on the part of many students when seeing the first post, but it's not immediately obvious to them what the error in reasoning is.
- It invites students to "Construct viable arguments and critique the reasoning of others," one of the eight Standards of Mathematical Practice.
- It allows the students to see adults disagreeing with each other in a civil and respectful way.
I hope I will have a chance to do this activity again. I think my students got a lot out of it.