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Smiling Man Lesson Plan

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Lesson Plan #: AELP-ALG0003
Submitted by: Jeff Barrett
Email: barrettjeff51@hotmail.com
School/University/Affiliation: Lakeview Jr.-Sr. High School Date: May 31, 1999

Grade Level(s): 6, 7, 8, 9, 10, 11, 12, Adult/Continuing Education

Subject(s):

  • Mathematics/Algebra

Duration: 1 class session Description: I cannot take credit for the smiling man. It was presented to me in a pre-algebra class many years ago. It is used in factoring an expression as well as a FOIL method substitute.

Goals: Students will engage in factoring problems.

Objectives: The students will factor trinomials with 90% accuracy and use the smiling man to check if the factoring is done correctly.

Materials:

  • pencils and paper

Procedure: Usually given by board examples and teacher lead discussions.

FOIL: (x+2) (x+3)

  • The student draws an arched line from the top of one x to the top of the other x. [x multiplied by x equals x2 ]
  • Next, the student draws a U-shaped line from the bottom of the first x to the bottom of the 3. [x multiplied by 3 equals 3x]
  • Then the student draws a U-shaped line from the bottom of the 2 to the bottom of the second x. [2 multiplied by x equals 2x]
  • Lastly, the student draws an arched line from the top of the 2 to the top of the 3. [2 multiplied by 3 equals 6]

    • If done correctly you see two arched lines forming something like eyebrows. The outer facing ( ) form loosely the ears, and the lines facing up in a U-shaped pattern where the two numbers are added form the nose and mouth. Students should get the following result when combining terms: x2 +5x +6.

    Give students the following trinomial and have them factor it, checking their results using the smiling man: x2 -5x +6

    Assessment: Informally assess students during class work. Ask for volunteers to go to the board to demonstrate the smiling man technique.

    Special Comments: I have used this extensively with at-risk students in prep. for their GED and found it to be quite a good memory trick.

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