Simplifying

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Lesson Objective: Students will be using the fraction keys on the TI-73 to learn how the calculator simplifies fractions, looking for the greatest common factor, and then trying to simplify fractions by using the greatest common factor.

Supplies and Materials:

bulletTI-73 calculators
bulletActivity Sheet
bulletHomework (pdf format)
bulletAnswers to Activity Sheet
bulletOverhead Projector
bulletOverhead TI-73 Calculator

Show students how to enter a fraction using the b/c key.

Show students how to simplify the fractions and notice whether the fractions can be simplified.

Give students several fractions to simplify. As students simplify the fractions they are to decide and record what factor the calculator used to simplify the fraction. They are to repeat this step until the fraction can no longer be simplified anymore (the down arrow disappears)

Ask students to use the factors to find the greatest common factor of the numerator and denominator.

Students are to study your chart carefully and think about:

bulletWhat numbers the calculator uses to simplify these fractions?
bulletWhat do you notice about the order in which the factors are chosen?
bulletHow can you determine the greatest common factor of the numerator and denominator?

The students will be asked to try some additional fractions, but this time they will be trying to simplify the fraction using the greatest common factor. The students are to write down their guess at the greatest common factor and then use the Simp key with the greatest common factor to simplify the fraction. If the down arrow disappears then the fraction is simplified. They score 1 point. If it doesn’t disappear they must enter a second greatest common factor by pressing Simp and the second greatest common factor. They should record their score as 2. Hopefully they will get the fraction simplified in one or two steps. If they not they score three points.