Monday, July 31, 2017

Thoughts on Subtraction

Est. reading time: 20 min

Prologue

My first advice on teaching, when I first became a TA in my Master's program, was a 2-page list of Do's and Don'ts. I don't remember most of them, or even how many they were but I do remember the first three.

  1. Know more than your students
  2. Know a lot more than your students
  3. Never tell your students everything you know.
This advice comes back to me approximately once a month, and its meaning always has subtle differences from the last time. I think it's extremely important advice. It's probably my most used benchmark for deciding how to participate in all sorts of discussions. The first point is a little "duh," but the second point makes you stop and meditate a little on the importance of the first. For anyone who has taught for more than 10 years, you get a sense of why 1 and 2 are important. But then, there's the importance of 3.  I thought 3 was a little silly and perhaps just a tad elitist for the first few years of teaching. But then, little by little, the power of 3 has crept up. I feel like, for me at least, there is a lot of wisdom in 3. Especially when it follows 1 and 2.

Here's an example.


Subtraction has been bothering me for some time now, and I've only recently started paying attention to this bother. I have been evolving the ways I've guided conversations around subtraction for the past few years, and I generally feel good about how the conversations go. However, I am always keenly aware of what parts of the conversation I'm leaving out (à la 3),  and I'm wondering what parts I should start adding in (yes, I note the pun of this sentence).

Sunday, July 30, 2017

Subtraction Survey Says!

These are the results from my survey, as of sometime today. Here I'm simply recording the results, unabridged, and with very little of my personal input. If you're interested in the greater context in which I collected this input, you can find it here.

The survey was posted on Twitter. I've left the survey open, in case you want to experience it first-hand, but I'm probably never going to go back to look at it.


The survey asks the same question, Does this picture show the operation 9–2? about six different pictures, and asks people to explain why they answered the way they did. Notice that the platform I used for collecting the survey was Desmos Activity Builder, so the results are stated with the participants being called "students."