Posted in Math investigations, Teaching mathematics

What is cognitive conflict approach to teaching?

According to Piaget, knowledge is constructed when a learner encounters input from the environment and incorporates the new experiences to his/her existing schemes and mental structures (assimilation). When this new assimilated information conflicts with previously formed mental structures, the result is called disequilibrium – a cognitive conflict. This state of disequilibrium motivates the learner to seek equilibrium. The cognitive conflict approach to teaching is based on this assumption – that learners will seek this equilibrium.

Cognitive conflict approach to teaching exposes students in  situations where some of their existing understandings about an idea or a topic no longer hold. A famous example on this is the Chords and Regions activity:

Find a way of predicting the maximum number of regions created by chords connecting n points.

This activity is usually used to challenge students thinking that patterns observed will always hold true and that patterns can be used as proof. The pattern observed will not hold true for n > 5. You can read the result of this activity in this paper Chords and Regions.

The assumption that learners will seek equilibrium when they are put in a situation of disequilibrium, when they experience cogntive conflict isn’t often the case. In fact, a common challenge faced by the cognitive conflict approach is that students often possess ‘contradictory understandings’ (from a mathematical point of view) but they don’t feel the need to address the inconsistencies in their understandings. This is the reason why it is very hard to correct a misconception. Also, students often do not see the importance (or necessity) to engage in a process of modifying their understandings to resolve the contradictions and they tend to treat the contradictions as exceptions (Stylianides & Stylianides, ICME-11). In the above activity for example, instead of being challenged, students can just accept the fact that the pattern stops after n=5 and not try to think of a more general rule to cover all cases. It is also possible that students can just say Next time I’ll try up to 10 cases before generalizing. This is now the challenge to the teacher. As a teaching approach, the use of cognitive conflict has a lot of potential but it needs more than simply using the appropriate task to create the conflict. Our students can be very resilient.

Mary Pardoe via LinkedIn discussion suggests that a strategy that encourages students to confront, rather than avoid, a cognitive conflict is to challenge small groups of students to reach a group conclusion (about the situation) with which everyone in the group agrees. Students who individually might respond differently to the ‘conflict’ will usually then try to persuade each other that their own points of view are correct, and so they are motivated to explain and discuss their thinking. Sample teaching using this approach is described in Using cognitive conflict to teach solving inequalities.

Common misconceptions are also rich sources of tasks for creating cognitive conflict. Click the link Mistakes and Misconceptions and Top 10 Errors in Algebra for sample of tasks.

You may want to check the book below to get more ideas on teaching mathematics.

Constructing Knowledge for Teaching Secondary Mathematics: Tasks to enhance prospective and practicing teacher learning (Mathematics Teacher Education)

 

Posted in Algebra, Math videos

Top 10 errors in algebra

Mathematics is indeed a universal language. Even errors are universal. Here are the top ten errors in algebra which are beyond borders and colors.

#10. Squaring the negative. A minus a squared unless it’s been snared: -8^2\neq 64

#09. Logarithms: The log of the sum ain’t the sum of the log: \log(a+b)\neq\log_a+log_b

#08. Shifting function: Add to y go high, add to x go west: y = (x+3)^2

#07. Inequality: Multiplying the inequality by a negative flips the inequality: -3(x<5) \neq -3x<-15

#06. On exponents: When in doubt, write it out: x^4 = x.x.x.x

#05. Fractional exponent: Don’t flip over the root. 25^{\frac{1}{2}} \neq \frac{1}{25^2}

#04. Subtraction: Don’t forget to share the minus and the negativity. x-(3+x) \neq x-3+x

#03. Cancellation: Cancel factors, not individual terms. \frac {x}{x-5} \neq \frac{1}{-5}

#02. Quadratics: Remember exponents 2, answers 2. x^2=25, x=5, x=-5

#01. Squaring: Don’t forget to FOIL. (x-3)^2 \neq x^2 -9.

Here is a funny video of common algebra mistakes listed above: Continue reading “Top 10 errors in algebra”

Posted in Misconceptions, Number Sense

Technically, Fractions are Not Numbers

It is misleading to put fractions alongside the sets of numbers – counting, whole, integers, rational, irrational and real. The diagram below which are in many Mathematics I (Year 7) textbooks is inviting misconceptions.

WRONG WAY

Fraction is a form for writing numbers just like the decimals, percents, and other notations that use exponents and radicals, etc.

The fraction form of numbers is used to describe quantities that is 1) part of a whole, 2) part of a set, 3) ratio, and 4) as an indicated operation. Yes, it can also represent all the rational numbers but it doesn’t make fractions another kind of number or as another way of describing the rational numbers. Decimals can represent both the rational and the irrational numbers (approximately) but it is not a separate set of numbers or used as another way of describing the real numbers! Note that I’m using the word number not in everyday sense but in mathematical sense. In Year 7, where learners are slowly introduced to the rigor of mathematics and to the real number system, I suggest you start calling the numbers in its proper name.

I prefer the Venn diagram to show the relationships among the different kinds of numbers like the one shown below:

The Real Number SYSTEM
The Real Numbers

The diagram shows that the set of real numbers is composed of the rational and the irrational numbers. The integers are part of the set of rational numbers just like the counting numbers are members of the set of whole numbers and the whole numbers are members of the set of integers. The properties of each of these set of numbers can be investigated. We do not investigate if fraction is closed or is commutative under a certain operation for example, but we do it for the rational numbers.

You may want to know why we invert the divisor when dividing fractions. Click the link.