Teaching Algebra with Manipulatives

Using Overhead Manipulatives
(Use with Algebra 1, Lesson 8-5)
Adding and Subtracting Polynomials
Objective Add and subtract polynomials using models.
Materials
• polynomial models transparency*
• overhead algebra tiles*
• transparency pen*
• blank transparencies
• colored acetate sheets (optional)
* available in Overhead Manipulative Resources
Demonstration 1
Adding Polynomials
• Use the polynomial models transparency to explain guidelines for using
algebra tiles.
• Remove the transparency. Place a blank transparency on the screen. Tell
students you want to find the sum of (2x 2 3x 2) and (4x 2 x 4).
Write the sum on the transparency. Ask students to model the two
polynomials.
2x 2 3x 2 4x 2 x 4
x 2 x 2
x x x
1 1
x 2 x 2
x
x 2 x 2 1 1 1 1
• Inform students that to find the sum, you must combine like terms and
remove all zero pairs. Ask them what polynomial model remains.
2x 2 4x 2 Complete the addition sentence on the transparency.
2x 2 4x 2
x 2 x 2 x x x
1 1
x 2 x 2
x
x 2 x 2 1 1 1 1
© Glencoe/McGraw-Hill 138 Teaching Algebra with Manipulatives