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Teaching Algebra with Manipulatives

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Chapter<br />

12<br />

Rational Expressions and Equations<br />

<strong>Teaching</strong> Notes and Overview<br />

Using Overhead<br />

<strong>Manipulatives</strong><br />

Dividing Polynomials by Monomials<br />

and by Binomials<br />

(pp. 195–196 of this booklet)<br />

Use With Lesson 12-5.<br />

Objective Dividing polynomials by monomials<br />

and by binomials using algebra tiles.<br />

Materials<br />

algebra tiles*<br />

product mat transparency*<br />

transparency pen*<br />

blank transparencies<br />

* available in Overhead Manipulative Resources<br />

This demonstration contains two activities.<br />

Both activities use algebra tiles and the area<br />

of a rectangle to model dividing polynomials.<br />

Students need to know what the 1 tile, x tile,<br />

and x 2 tile represent.<br />

• Demonstration 1 shows how to use algebra<br />

tiles to divide 2x 2 6x by 2x. First, 2x 2 6x<br />

is modeled. From this model, the two x 2 tiles<br />

and one x tile are placed on the product mat<br />

transparency. Students are asked to build the<br />

rectangle <strong>with</strong> the remaining tiles on the<br />

mat. The length is 2x and the width is x 3.<br />

The width, x 3, is the quotient of 2x 2 6x<br />

and 2x.<br />

• Demonstration 2 models the quotient of x 2 <br />

5x 6 and x 2. Like in Demonstration 1,<br />

x 2 5x 6 is modeled using algebra tiles.<br />

Then the x 2 tile and two of the 1 tiles are<br />

placed on the product mat. Next, students<br />

are asked to build the rectangle <strong>with</strong> the<br />

remaining tiles on the mat. The length is<br />

x 2 and the width is x 3. The width, x 3,<br />

is the quotient of x 2 5x 6 and x 2.<br />

Provide additional examples showing how to<br />

use algebra tiles to model dividing polynomials.<br />

Let students discover that algebra tiles cannot<br />

be used to divide polynomials <strong>with</strong> non-zero<br />

remainders. The latter situation is addressed in<br />

the <strong>Algebra</strong> Activity on page 667 of the Student<br />

Edition. Discuss <strong>with</strong> students how they can<br />

divide <strong>with</strong>out using models.<br />

Answers<br />

Answers appear on the teacher demonstration<br />

instructions on pages 195–196.<br />

<strong>Algebra</strong> Activity<br />

Recording Sheet<br />

Dividing Polynomials<br />

(p. 197 of this booklet)<br />

Use With the activity on page 667 in Lesson<br />

12-5 of the Student Edition.<br />

Objective Divide a polynomial by a binomial<br />

using algebra tiles.<br />

Materials<br />

algebra tiles*<br />

* available in Overhead Manipulative Resources<br />

Have students read and study the illustration<br />

of x 2 3x 2 divided by x 1. Discuss the<br />

process as a class. Form groups of two or three<br />

students to use algebra tiles to complete the<br />

<strong>Algebra</strong> Activity. Ask students to draw the<br />

completed rectangle for each of the Exercises<br />

1–4 and to draw around the dimension that is<br />

the quotient. Discuss the quotients. Next, have<br />

them work Exercise 5. Students cannot model<br />

this division using algebra tiles, because of the<br />

existence of a non-zero remainder. Discuss <strong>with</strong><br />

students how they can divide <strong>with</strong>out using<br />

models.<br />

Answers<br />

See Teacher Wraparound Edition p. 667.<br />

Mini-Project<br />

Rational Roundup<br />

(p. 198 of this booklet)<br />

Use With Lesson 12-9.<br />

Objective Solve rational equations.<br />

Add, subtract, multiply, and divide rational<br />

expressions.<br />

Materials<br />

scissors<br />

<strong>Algebra</strong> 1—Chapter 12<br />

© Glencoe/McGraw-Hill 193 <strong>Teaching</strong> <strong>Algebra</strong> <strong>with</strong> <strong>Manipulatives</strong>

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