Question

Is \[9\] a composite number?

Answer 1

Hint: We use the concepts of composite numbers and definitions of composite numbers to solve this problem. We will look at some examples of composite numbers and also some examples of numbers which are not composite numbers (which are called as prime numbers).

Complete step by step answer:
In mathematics, there are two kinds of numbers.
They are prime numbers and composite numbers.
A prime number is a natural number greater than 1, which is divisible only by 1 and the number itself.
So, in other words, numbers which have only two divisors have been called prime numbers.
All other numbers other than prime numbers are called composite numbers.
For example, take the natural number 2.
So, the number 2 is only divisible by two numbers which are 1 and 2. So, 2 is a prime number.
These are the few prime numbers:
\[2,3,5,7,11,13,17,19,23,29,31,......\]
All other natural numbers other than prime numbers are called composite numbers i.e., numbers which have more than two divisors are called composite numbers.
Every composite number can be written as a product of prime numbers.
For example, take number 24. It is divisible by 1, 2, 3, 4, 6, 8, 12 and 24.
So, it has more than two divisors. So, it is a composite number.
So, we can write 24 as, \[24 = 2 \times 2 \times 2 \times 3\]
Now, take the number 9.
It is divisible by 1 and 9 and also by 3.
So, it has three divisors. So, it is a composite number.

Note:
The number 1 is neither a prime number nor a composite number. All composite numbers can be written as products of prime numbers. Divisors of a number are also called as factors. So, a number with more than two factors is called a composite number. We can find composite numbers by applying divisibility rules of prime numbers.