1.03 Prime and composite numbers
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When we looked at factors of numbers , we found that some numbers only had themselves and 1 as factors, while others have more factors. Try this problem to review finding the factors of a number.
Exploration
Drag the sliders to find multiples of numbers from 1 to 12.
The number sentence shows us multiples of the numbers on the left, and factors of the number on the right. e.g. 6\times 8=48 means that 6 and 8 are factors of 48, and that 48 is a multiple of 6 and of 8.
Examples
Example 1
Which of these numbers is 6 a factor of?
6\times 8=48 means that 6 and 8 are factors of 48, and that 48 is a multiple of 6 and of 8.
Prime and composite numbers
What are prime and composite numbers? How can we determine if a number is prime or composite? Let's take a look and see.
Examples
Example 2
True or False? 40 is a composite number.
Example 3
True or False? 79 is a prime number.
Every whole number greater than 1 is either a prime number or a composite number
All even numbers greater than 2 are composite numbers
To be a prime number, a number can only have itself and 1 as factors
0 and 1 are not prime or composite numbers