Tag Archives: education

The Triangleman Decimal Institute [TDI]

In recent weeks, I have written several times about decimals and their treatment in curriculum. In discussions surrounding that writing, it has become clear to me that everyone involved in children’s learning of decimals can both learn and contribute to the learning of others.


Which is why I am excited to announce…

The Triangleman Decimal Institute

For seven weeks, starting Monday, September 30, I will invite all interested parties to an online conversation about decimals and learning decimals.

Each Monday, I’ll have a new post here to launch and focus our discussions. Comments will be closed in order to move the discussions to more productive venues (see below).

You may participate in any way that you like, including the following:

  1. Self study. Read at your leisure. Discuss with yourself, your colleagues, your spouse and/or your Australian Labradoodle.
  2. Twitter. I invite you to use the #decimalchat hashtag to respond, argue, offer evidence and discuss.
  3. Canvas. It is no secret that I love this LMS. I have established a course in Canvas. The course is public, free and you may self-enroll. We will mainly use the discussion forums there, which function MUCH better than WordPress comments for our purposes. I will establish a new discussion forum there for each week’s post, but students (i.e. you) can also create discussions.

You may come and go as you please.

My promise to you is to keep myself on the schedule in the syllabus below and to engage to the extent possible in the discussions on Twitter and Canvas.


Come join us for some or all of the following.

Week 1 (Sept. 30): Decimals before fractions?

Week 2 (Oct. 7): Money and decimals.

Week 3 (Oct. 14): Children’s experiences with partitioning.

Week 4 (Oct. 21): Interlude on the slicing of pizzas.

Week 5 (Oct. 28): Grouping is different from partitioning.

Week 6 (Nov. 4): Decimals and curriculum (Common Core).

Week 7 (Nov. 14): Summary and wrap up.

There will be no grades, tests or tuition. Just the love of knowledge and the collective passion of teachers wanting to do their best.

See you in class on Monday!

Note from Canvas:

This course has enabled open enrollment. Students can self-enroll in the course once you share with them this URL:  https://canvas.instructure.com/enroll/MY4YM3. Alternatively, they can sign up at https://canvas.instructure.com/register  and use the following join code: MY4YM3


Pep talk for the coming school year

Here’s a transcript of something I said recently. It was in response to a common question, “That’s a great idea, but how can we fit that in when there are so many things we have to get done?”

That’s one of the things I struggle with. It’s clear to me that since I left the public school classroom in 2000, that the kinds of pressures and constraints under which teachers operate are quite a bit different. I have seen, over the years I’ve been working with teachers, a great degrading of teachers’ feelings of autonomy and ability to make meaningful decisions for their kids; particularly large decisions about curriculum, but even sometimes on a day-to-day lesson basis.

All I can say is that when I do work with teachers who are under those kinds of constraints, the thing that I try to remind them is that curriculum—whether district curriculum or published textbooks—is really a framework, and it is a teacher’s job and responsibility to flesh out that framework in ways that will create powerful mathematics learning for kids.

So I encourage you to not stray from the agreements that are necessary to make as a district or as a school—in terms of sequence of content, or basic resources we use in our classrooms—but that we have a tremendous amount of leeway in terms of setting the tone. What kinds of questions are we going to ask? What kinds of mathematical contributions are we going to value from kids?

I think it’s important for us to retain that responsibility, even when we’re feeling disempowered by forces that are outside our control.