The document discusses the concept of highest common factors (HCF) and prime factorization, outlining steps to find HCF by breaking numbers into their prime factors. It includes a practical example comparing the numbers 60 and 72, illustrating that their HCF is 12. The document further presents exercises for identifying HCF of additional number pairs, with answers provided.

1. Prime Factorization
NUMBERS AND
NUMBER SENSE

2. PRIME FACTORIZATION
 When we study multiplication there are certain terms that
are associated with it.These terms include:
Factors
Multiples
Highest Common Factors (HCF)
Lowest Common Multiples (LCM)
In this video we will discuss Highest Common
Factors.

3. PRIME FACTORIZATION
HIGHEST COMMON FACTOR
 In this case you are comparing two numbers.To find the
highest common factors of these numbers you do the
following:
1. Break the numbers down into their prime factors
2. Multiply the prime factors common to both numbers
3. The result is your Highest Common Factor (the largest
factor that can go into both numbers).
Let’s look at a live illustration.

4. PRIME FACTORIZATION
HIGHEST COMMON FACTOR
Let’s compare the two numbers 60 and 72.
We have to find their HCF.
Numbers 60 72
Factors 6 x 10 6 x 12
Prime Factors 2 x 3 2 x 5 2 x 3 2 x 2 x 3
The factors common to both 60 and 72 are 2, 2 & 3.
Multiply them to get 12; so the HCF of 60 & 72 is 12

5. PRIME FACTORIZATION EXERCISE
 Find the highest common factors of the numbers below:
28 and 32 21 and 42 33 and 110
Draw the table and fill in the answers either in your book or
on the computer.
28 32 21 42 33 110

6. PRIME FACTORIZATION EXERCISE
 The answers are in red below. Did you identify them?
28 and 32 21 and 42 33 and 110
HCF = 2 x 2 = 4 HCF = 3 x 7 = 21 HCF = 11
AWESOME SAUCE!
28 32
2 2
2 2
7 2
2
2
21 42
3 2
7 3
7
33 110
3 2
11 5
11

7. PRIME NUMBERS RECAP
 In this lesson you learned:
How to define the term highest common factor
The highest common factor of two numbers
GREATWORK!