Lesson Plan #: AELP-ATH0027 ** Submitted by:** Stephanie Englert

** Email:** stephanieenglert@hotmail.com

** School/University/Affiliation:** Graceland College Lamoni, Iowa ** Date:** February 25, 1999

**Grade Level(s):**4, 5, 6

** Subject(s):**

- Mathematics/Arithmetic

** Duration:** 20 minutes.

** Description:** This lesson is started with a brain teaser about averages. The lesson uses information about averages and has the students use their own examples.

** Goals:** To introduce the concept of averages and to allow the students to interact with one another.

** Objectives:** To teach the idea of averages and divisors of three.

** Materials:** pencil, paper

** Procedure:**

Brain Teaser: Have the students pick three consecutive numbers. Have the students add them together. They will then tell you the number. The teacher then divides this number by three, and knows that the student’s numbers were the number before, the number found by dividing by three, and the next consecutive number.

Lesson: Have the students get with a partner and practice averages by adding the ages of their family members and then dividing by the number of family members. They can also figure out the divisors of three by the brain teaser. The rule is if the digits in the number added can by divided by three, then that number is divisible by three.

** Assessment:** The students can first assess themselves by checking the other partner’s average answers. They can then be tested orally by the teacher, and then by a pencil and paper exam. This will allow plenty of practice before they are graded by a test.

** Useful Internet Resource:**

Brain Teasers

http://www.eduplace.com/math/brain/index.html