## I. Initial Planning

**Content to be covered:**

The content of this lesson begins with review of prime and composite numbers

and moves on to the definition of a factor and factor pairs. A factor game will
be

introduced to enhance the lesson. Comparisons of different numbers and their
factors

will lead to finding the greatest common factor by using the listing method .

**Objectives:**

• Students will be able to (SWBAT) define the term factor .

• SWBAT define the term factor pair and give examples.

• SWBAT play the Factor Game.

• SWBAT list the factors of two different numbers and compare them.

• SWBAT find the greatest common factor of two numbers using the listing

method.

**North Carolina Standards**

Competency Goal 1: The learner will understand and compute with rational
numbers .

Objective 1.05: Develop fluency in the use of factors, multiples, exponential

notation, and prime factorization.

Objective 1.04: Develop fluency in multiplication and division of non - negative

rational numbers.

1.04 a: Analyze computational strategies

**• Prior knowledge needed:**

• Definitions of prime and composite numbers (This will be reviewed at the

beginning of the lesson.)

• Some comfort in identifying prime and composite numbers introduced in the

previous lesson

• Fluency with multiplication and division (tested for at beginning of unit)

• Internet knowledge

• Knowledge of the divisibility rules and how they apply (taught in lesson 3)

**Materials needed:**

• chalk board or dry erase board with chalk or dry erase markers

• computers

• overhead projector

• different colored pens/markers and pencils

• 3 different handouts that are front and back (shown below lesson plan)

**Review**

A ______________ is a number that can

______________ be divided evenly by one and itself.

Examples: 2, 3, 5, 7, 17, 23

A ______________ is a number that can be

divided evenly by numbers ______________ than one

and itself.

Examples: 4, 6, 8, 9, 15, 24, 32

**New Stuff**

What is a factor?

______________

______________

What are the factors of 2?

Factors of 3? |
Factors of 5? |
Factors of 4? |

Factors of 6? |
Factors of 8? |
Factors of 12? |

What is a factor pair?

(hint: pair means two!)

______________

______________

Examples:

3 and 4 are a factor pair of 12

2 and 3 are a factor pair of 6

4 and 5 are a factor pair of 20

How do I write out a factor pair?

Examples:

3 and 4 |
2 and 6 |
6 and 5 |

3,4 |
2,6 |
6,5 |

List two factor pairs of each number

a) 36 |
b) 20 |

c) 56 |
d) 24 |

e) 35 |
f) 40 |

**More New Stuff**

Let’s compare the factors of two different

numbers

1. List all factors of 24

2. List all factors of 36

What factors do they have in common?

These are called ______________

Definition of Greatest Common Factor (GCF):

The ______________ is the

______________ umber that divides _____________

(without a remainder) into each number in a set or

group .

**Examples:**

1) Factors of 16: 1, 2, 4, 8, 16

Factors of 42: 1, 2, 6, 7, 14, 42

Common factors: 1 and 2 GCF: 2

2) Factors of 45: 1, 3, 5, 9, 15, 45

Factors of 40: 1, 2, 4, 5, 8, 10, 20, 40

Common factors: 1 and 5 GCF: 5

3) Factors of 12: 1, 2, 3, 4, 6, 12

Factors of 8: 1, 2, 4, 8

Common factors: 1, 2, and 4 GCF: 4

**Back to notes**

What are the common factors of 24 and 36?

What is their greatest common factor?

Individual Exercises:

List the factors of each pair and circle the GCF .

1. 6 and 14 |
2) 4 and 10 |

3) 18 and 22 |
4) 26 and 13 |

5) 30 and 42 |
6) 48 and 56 |

7) 50 and 120 |
8) 70 and 130 |

**Homework**

1. List all factors for each of the following numbers.

Please write your answers using factor pairs.

(You may use your calculator )

a) 88 |
b) 96 |

c) 102 |
d) 120 |

e) 30 |
f) 95 |

2. List the factors of each set of numbers. **Circle the**

common factors and write down the GCF.

a) 76 and 52 |
b) 18 and 45 |

c) 72 and 48 |
d) 81 and 40 |

e) 29 and 87 |
f) 44 and 68 |

**Extra Credit:**

Write out all of the factor pairs for each number.

1) 188

2) 236

Find List the common factors and the GCF for the sets

of numbers below. (Hint: you will have to factor each

number first!)

1) 36, 12, and 42

2) 8, 40, and 32