Page 43 - NUMINO TG_6A

Workbook Which Is the Greatest?

101-B1-1 101-B1-2

Common Factors and the Greatest Common Factor 2. Use the GCF of the two numbers to find the common factors.
1. Find the GCF of the two numbers.
Example
Example
Common factors of two numbers are the same as the factors of the GCF of the
The largest number among all the common factors is called the greatest two numbers.
common factor (GCF).

12 , 16 Factors of 12: 8 , 28
Factors of 16:
The GCF of 8 and 28: 4
Common factors of 12 and 16: Common factors of 8 and 28:

The GCF of 12 and 16:

a. 27 , 36 Factors of 27: a.
30 , 45
Factors of 36:
The GCF of 30 and 45: 15
Common factors of 27 and 36: Common factors of 30 and 45:

The GCF of 27 and 36:

b. 32 , 72 Factors of 32: b.
32 , 80
Factors of 72:
The GCF of 32 and 80: 16
Common factors of 32 and 72:
Common factors of 32 and 80:
The GCF of 32 and 72:

c. 28 , 56 Factors of 28: c.
28 , 42
Factors of 56:
The GCF of 28 and 42: 14
Common factors of 28 and 56:
Common factors of 28 and 42:
The GCF of 28 and 56:

Objective Learn how to find the greatest Objective Learn how to find common
common factor. factors.

Textbook Reference Lead-In Textbook Reference Lead-In

101-B2-1 101-B2-2

Using Prime Factorization to Find the GCF 2. Find the GCF as shown in the example.
1. Find the greatest common factor as shown in the example. Example
6, 18
Example 6 18

20 , 30 a. 9, 15
20 9 15
30 20
30

a. 28 , 42 The GCF: 7 The GCF: The GCF:
28 42
76 28 b. 27, 30 c. 12, 28
42 27 30 12 28
b. 18 , 30 The GCF:
18 30 The GCF: The GCF:
18
30 d. 20, 42 e. 16, 24
The GCF: 20 42 16 24

The GCF: The GCF:

Objective Find the greatest common factor Objective Find the least common multiple
by prime factorization using a ladder diagram.

Textbook Reference Activity 1 Textbook Reference Activity 1

026 NUMINO Teacher s Guide