Why it is bad habit to introduce math concepts through their definitions

By | April 7, 2011

In my earlier post on the meaning of understanding, I describe understanding of mathematics as making connections: To understand is to make connections. These connections are not done in random.  Concepts are linked with other concepts in order to create a richer image for the new concept that is being learned. To understand therefore is to form concept image. And a concept image is not formed by defining the concept. The definition of a concept is different from the concept image. Let me share with you a an excerpt from my paper which discusses this idea. You can view the references here.

Understanding the definition does not imply understanding the concept. In order to understand a concept one must have a concept image for it. One’s concept image includes all the non-verbal entities, visual representations, impressions and experiences that are created in our mind by a mention of a concept name (Vinner, 1992). Vinner stressed that the concept definition is not the first thing that is learned in understanding a concept but the experiences associated with it, which becomes part of one’s concept image. Vinner believes that in carrying out cognitive tasks, the mind consults the concept image rather than the concept definition.

Vergnaud (1997) also noted, “it is misleading, even in mathematics [despite its precision in defining], to consider that the properties of a concept are self-contained in its definition” (p. 5). To study and understand how mathematical concepts are develop in students’ minds through their experience both in and outside school, Vergnaud proposed that one needs to consider a concept C as a three-uple of three sets:

C = (SIR)

S: the set of situations that make the concept useful and meaningful.

I: the set of operational invariants that can be used by individuals to deal with these situations.

R: the set of symbolic representations, linguistic, graphic or gestural that can be used to represent invariants, situations and procedures (p. 6)

What are these telling us mathematics teachers? Well, firstly, that it is not a good practice to start with concept definitions and secondly that it is important to design learning experiences that will create and enrich the concept image because it is then and only then when students can relate to the definition. Definitions are already an abstraction of the concept. For example, if you give the child the definition of a dog, do you think he’d recognize one if he sees one? Kidding. In order to be suitable to learners , a definition must consist of concepts known to the learner (Cobb). It should rely, as far as possible, on the intuition of the student (Fischbein). It should be within the grasp of the learner (inside the learner’s zone of proximal development — Vygotsky).

All the lessons and tasks I present in this blog target the creation of concept images. For example, on the teaching of integers, the following lessons provides the ground work for understanding integers.

  1. A problem solving approach for introducing integers
  2. Sorting number expression
  3. Introducing the integers via number line with a twist
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4 thoughts on “Why it is bad habit to introduce math concepts through their definitions

  1. Pingback: » Theories and ideas behind the math lessons in this blog » Mathematics for Teaching

  2. cani

    Excellent post. In an ideal world this would be possible. Yet teachers are under pressure to produce studnets who can past tests. In the UK, we have league tables, and schools are judged on the number of A-C grades students get, especially in maths. So most schools teach to the test, and there is too much to teach in any great detail, especially for those doing higher papers. Teachers have to go and teach instructionally and through definitions and repeated practice.

    As a student, I learnt maths like everyone did, through repeated practice of algorithms. What made me get maths was looking for patterns while doing all these practices and finding commonalities with old knowledge, all on my own.

    Here is an article which might be of interest to you and your viewers. IT is about the debate over the “khan Academy” videos, basically an instructional and passive way of learning, which is being promoted by Bill Gates. (i know they are long, but check out the first link)





    There is also a good video on the research and problems of just listening to instructions and learning


    sorry dont know how to do the internet links

  3. Guillermo Bautista

    I totally agree. Definitions are abstractions of mathematical concepts, so I think, during the crucial stage of learning (elementary and middle school), students should understand the concept first before you give them the definition. In fact, lessons should be taught in order to lead students to formulate their own definitions.

    In higher math, of course, we know that most lessons starts with definitions.

  4. Bon Crowder

    I get quite annoyed at those who think that a situation much be around for a student to enjoy math. Is it not possible for a kid to enjoy the definitions for their own sake?

    I did – here’s the story of how I enjoyed the definitions and the teacher didn’t get it!

    Really – the bottom line is that teachers should watch what a kid needs and supply them with it. If they need the (S, I, R) method, great. Give it to them. If they love math for the sake of math – then quit trying to force the situations on them.


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