## Friday, July 1, 2011

### Unlocking Fractions for the Confused and Bewildered

Adding, subtracting, multiplying, and dividing fractions are something that every student should learn, but often numerous students are left behind in the mathematical dust when a math textbook is followed page by page. Finding the lowest common denominator, changing denominators, not changing denominators, finding a reciprocal, and reducing to lowest terms are complex issues and often very difficult for many students.

I presently teach at a community college, and my students are mathphobics whose mathematical anxiety is hard to hide. One of my classes entitled, Decimals, Fractions and Percents, is geared to those undergraduates who have never grasped fractions. This article encompasses how I teach adding fractions so these students can be successful. Specifically, let's look at adding fractions using the Cross Over Method.
Here is a typical fraction addition problem.
After writing the problem on the board, rewrite it with the common denominator of 6.

Procedure:

1) Ask the students if they see any way to multiply and make a 3 using only the numbers in this problem.

2) Now ask if there is a way to multiply and make 2 using just the numbers in the problem.

3) Finally, ask them to find a way to multiply the numbers in the problem to make 6 the denominator.

4) Instruct the students to cross their arms. This is the cross of cross over and means we do this by cross multiplying in the problem.
5) Multiply the 3 and 1, then write the answer in the numerator.

*Note: Always start with the right denominator or subtraction will not work.
6) Next multiply the 2 and 1 and write the answer in the numerator. Don’t forget to write the + sign. *Note: One line is drawn under both numbers. This is to prevent the students from adding the denominators (a very common mistake).
7) Now have the students uncross their arms and point to the right using their right hand. This is the over part of cross over. It means to multiply the two denominators and write the product as the new denominator.

9) Reduce to lowest terms when necessary.

It is important that students know the divisibility rules for 2, 3, 5, 6, 9 and 10. In this way, they can readily reduce any problem. In addition, it is extremely important that the students physically do the motions while they learn. This not only targets the kinesthetic learner but also gives the students something physical that will make it easier for them to remember. The pictures or illustrations for each technique benefit the visual/spatial learner. Of course, the auditory student listens and learns as you teach each method.
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 Fractions for the Confused

I have found these unconventional techniques work with most students, and I trust you will endeavor to give them a try in your classroom. A resource handout on how to add, subtract, multiply, and divide fractions is available by clicking on the yelling guy with fraction math phobia on your right.

#### 1 comment :

1. Thank you for the tips. All help is appreciated...especially with the Common Core's push with fractions.

I am happy to have found your blog!

Patti
One Class, One Sound