# math CHAPTER 2.3 FORM 1 By Kelvin

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## Presentation Description

math CHAPTER 2.3 FORM 1 By Kelvin

## Presentation Transcript

### Mathematics – Form 1:

Mathematics – Form 1 Chapter 2.3 By Kelvin

### Prime number:

Prime number Determining Prime Numbers 1 . A prime number is a whole number that can only be divided by itself and 1. 2 . Thus, 2, 3, 5, 7, 11, 13, 17,... are prime numbers. 3 . The first prime number is 2. 4 . To determine whether a given number is a prime number , carry out the following steps .

### Slide 3:

Steps 1: Divide the given number by prime numbers whose squares are less than it. Steps 2: If the given number cannot be divided exactly by all the prime numbers, than it is a prime number. Worked example Determine whether each of the following is a prime numbers or not. ( a) 45               (b) 73

Solution

### Worked example:

Worked example List all the prime numbers between 30 and 60. Solution Write down all the odd numbers between 30  and 60 and then cross out all the numbers divisible by 3, 5, 7. 31 , 33, 35, 37, 39, 41, 43, 45, 47, 49, 51, 53,  55, 57, 59   Therefore , the prime numbers between 30 and  60 are 31, 37, 41, 43, 47, 53 and 59.

### Worked example:

Worked example Find the sum of all the prime numbers which are less than 10. Solution Prime numbers which are less than 10 are 2, 3, 5  and 7. Therefore , its sum = 2+ 3 +5 +7 = 17

### Slide 8:

THANKS FOR SEE THIS CHAPTER…. THIS THE LAST OF THE CHAPTER 2.3…. NEXT CHAPTER IS COMING SOON AT 7 /3/2016 ….. 