Archive for February 5th, 2008

Multiplication of fractions – a cool visual

Tuesday, February 5th, 2008

As some of you know, I work part-time as a math paraeducator (a.k.a. “teacher’s helper”). In 6th grade, we have been studying multiplication of fractions. If your schooling was like mine, you probably were told, “This is how you multiply fractions,” then you were given a bunch of problems to do to get you used to the formula, and you never really UNDERSTOOD what multiplying a fraction times a fraction means, or why you end up with a smaller number as the answer.

I also know that some of you are home educators, so perhaps the following drawings will be useful to you in explaining this concept to your pupils.

This method, called the “brownie pan” method, uses visual aids, or manipulatives, drawn by the students. Here is how the student could illustrate the fraction 3/4:

brownie-pans1.jpg

Here is how the student could illustrate the fraction 2/3:

brownie-pans2.jpg

And, finally, this is how the student could illustrate the multiplication problem 2/3 of 3/4 OR 3/4 of 2/3 (Remember that the word “of” indicates the mathematical operation of multiplication.):

brownie-pans3.jpg

The sections of the brownie pan that are double-shaded show the numerator of the fraction product (How many pieces of the whole are we talking about?) and the total number of sections in the “brownie pan” shows the denominator of the fraction product (How many pieces total is the whole divided into?).

This is cool, is it not?

Do you have any questions, students?