LESSON 2 – PRIME FACTORISATION

Objectives:

At the end of the lesson, students should be able to write the prime factors of given numbers.

NOTE:

A prime number is a number that has only two factors, that is one and the number itself.

If a factor is a prime number, it is called a PRIME FACTOR.

To find the prime factor of a given number, divide the number by the smallest prime number which is a factor and then by the larger prime numbers as you move on.

There are several ways of finding the prime factors of a number.

This lesson will focus on the following.

List method

Factor tree method

Ladder method.   

Example 1

Using the list method, find the prime factors of the following.

1. 15

2. 24

Solution

1. 15 = 1 x 15

         3 x 5

Factors = {1, 3, 5, 15}

Prime factors = {3, 5}