Beacon Lesson Plan Library
Prime Factorization Mobile
Amelia McCurdy
Santa Rosa District Schools
Description
During this review lesson, students demonstrate their knowledge of prime numbers, composite numbers, and prime factorization using exponents to create a factor tree mobile.
Standards
Florida Sunshine State Standards
MA.A.1.3.1.7.1
The student knows word names and standard numerals for integers, fractions, decimals, ratios, numbers expressed as percents, numbers with exponents, numbers expressed in scientific notation, and numbers expressed using the square root radical.
MA.A.5.3.1.7.1
The student knows if numbers are prime or composite.
MA.A.5.3.1.7.3
The student determines the prime factorization of a composite number.
Florida Process Standards
Numeric Problem Solvers
03 Florida students use numeric operations and concepts to describe, analyze, communicate, synthesize numeric data, and to identify and solve problems.
Materials
- 3" x 5" Index cards (unlined)
- Yarn (cut into 6" to 8" lengths)
- Colored pencils, markers, or crayons
- Hole puncher
- Ceiling hooks (large paper clips or commercial)
Preparations
1. Prepare a mobile as an example.
2. Create sets of prime and composite numbers to assign to students.
Procedures
1. Review prime numbers, composite numbers, and prime factorization. Ask students to give you examples of prime and composite numbers. Review how to find the prime factorization using a factor tree and how to write the prime factorization using exponents. Provide opportunity for practice.
2. Describe the project. Assign two numbers to each student, one prime and one composite. After the students determine which numbers are prime and which are composite, they will plan their mobile by drawing a factor tree for the composite number. Encourage students to find several ways to create a factor tree and select one. Students are required to rewrite their number in prime factorization using exponents. Each number on their factor tree is one index card. On the back of their number card, the students will write the number in exponential form. Each line (tree branch) is a piece of yarn. Students need to determine how many cards and pieces of yarn are needed for their mobiles. See attached file for an example mobile.
3. Students will bring their plans to the teacher for approval and tell the teacher how many cards and pieces of yarn are needed for their project. Encourage students to be creative in their designs. For example, write the numbers in 3-D form.
4. After the projects are completed and graded, hang the mobiles for display in class.
Assessments
Scoring rubric for project:
Whole number correctly rewritten
3 points--correct and using exponents
2 points--correct and without exponents
0 points--incorrect
Identify prime number
3 points--correctly identifies prime number
2 points--correctly identifies with help
0 points--incorrect
Identify composite number
3 points--correctly identifies composite number
2 points--correctly identifies with help
0 points--incorrect
Design mobile
3 points--correct
2 points--correct with help
0 points--incorrect
Students who do not score at least 8 points will need additional instruction and practice.
Extensions
For lower level students, have students work in cooperative groups. For advanced students, students could create a mobile for numbers greater than 100. For pre-algebra students, use positive and negative integers. For algebra students, create a mobile for monomials.
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