Representations are tools for thinking, explaining, justifying. NB: Pape/Tchoshanov, 2001. pic.twitter.com/Nux9jP7Z4b— Matthew Oldridge (@MatthewOldridge) June 7, 2016
The Pape/Tchoshanov paper is instructive for teachers in getting kids to develop their own mental representations, and to get them out into the physical world.
In their words:
"We use the term representation(s) to refer to both the internal and external manifestations of mathematical concepts."
This is a huge argument for paying attention to your students' thinking, in order to make it visible. We need to help kids visualize representations of interesting mathematical concepts, in order to imagine them into being.
So we have two complementary aspects of mathematical representations:
-the act of representing (verb)
-the representation itself (noun)
This quite neatly corresponds to both NCTM and Ontario curriculum definitions of representation: as both process and product.
The authors propose a "'zone" of interaction between mental and physical interactions.
The nice example used is of "six"-a kid develops an internal mental image of "'six', then connects it to sets of six objects, the numeral 6, the written word "six", the spoken word "six", and so on.
As kids advance in math, we should encourage representational thinking. That is, building and having a repertoire of ways to externalize math concepts. Tables, graphs, tree diagrams, area models, arrays- these are all examples.
The authors put it nicely:
"the development of students' thinking skills requires a multiple representational approach."
Put simply: representations are tools for reasoning.
Two things to think about.
Kids often mathematize math tasks by drawing pictures with little or no mathematical content. Do these count as representations?
"Students often produce representations that lack meaning."
Manipulatives are generally a good thing, as long as they are accurate mathematical representations of the concept, the mathematics you are working on. Daniel Willingham presents this caveat here.
Manipulatives, if not chosen wisely, can get in the way of mathematical representation. Let the tool fit the task (and the math).
The end goal of representation is good communication. Can the student communicate their thinking, in words, or on paper, using mathematical representations?
Even better, can they start to see how different representations are connected? Do they see a table of values, a pattern made with cubes, a graph, and an algebraic expression as fundamentally the same thing?
How do they show the same math in different ways?
Fluency with multiple representations should be a goal of thinking math classrooms; we can help kids to visualize, conceptualize, and make real their understanding of powerful mathematics.