Question

Difference between composite and co prime numbers

Answer 1

Prime numbers:

Numbers which have only two factors 1 and the number itself are called prime numbers.

E.g 2 ,3 ,5, 7 ,11 ,13, 17 and so on are all prime numbers.

Of the first 100 numbers 25 are prime numbers.

Only 2 is an even prime number all prime numbers are odd.

Co prime numbers:

Numbers which do not have any common factor between them other than one are called coprime numbers.

Two natural numbers( not necessarily Prime) are coprime if their HCF is 1.
For e.g
(1,2) , (1,3), (3,4), (3,10), (3,8), (5,6), (17,23)

even two composite numbers can also be Prime. for e.g
(16,25), (84,65)

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Hope this will help you....

Answer 2

Difference between composite numbers and co-primes -

Composite Numbers -

A composite number is a positive integer that has a factor other than 1 and itself. For instance, 12 is a composite number because it is a positive integer and it has factors other than 1 and itself. 2, 3, 4, 6 are its factors other than 1 and itself. All even numbers greater than 2 are composite numbers. 2 is a prime number. The smallest composite number is 4.

Co Primes -

Co primes are set of numbers or integers which have only 1 as their common factor. Their highest common factor is 1. The co primes are also known as relatively prime or mutually prime numbers. 1 is co prime with every number. Any two successive numbers/integers are always co primes. 

Consider an example of set of two numbers such as 21 and 22.

Factors of 21 = 1, 3, 7 and 21 

Factors of 22 = 1, 2, 11 and 22

Here, 21 and 22 have only one common factor that is 1. So, these two number are co primes.