Question

The smallest composite number is ______.
(a) 2
(b) 4
(c) 1
(d) None of these

Answer 1

Hint: Understand the definition of prime numbers and composite numbers and take examples for better understanding. Now, find the smallest number which has more than two factors and select the correct option to get the answer.

Complete step by step answer:
Here, we are asked to find the smallest composite number. But first, we need to understand the meaning of composite numbers and its difference from prime numbers. So, let us know about them – by – one.
1. Prime numbers: - A prime number is a natural number, i.e. counting numbers, that has only two factors. That means a prime number is a number that is divisible by only two numbers. These two numbers will be 1 and the number itself. For example: - let us consider the natural number 7. 7 is only divisible by 1 and 7 itself that means it has only two factors 1 and 7. So, 7 is a prime number. Some other prime numbers are: - 2, 3, 5, 11, 13, … etc.
2. Composite numbers: - A composite number is a natural number, i.e. counting numbers that have more than two factors. That means a composite number is a number that is divisible by more than two numbers. In other words, we can say that a natural number which is not a prime is a composite number. For example: - let us consider the natural number 10. 10 is divisible by 1, 2, 5, and 10 itself which means it has more than two factors. So, 10 is a composite number. Some other composite numbers are - 4, 6, 8, 9, 10, 12,….. etc.
On reading the above paragraphs about prime and composite numbers we can clearly see that 4 is the first and smallest composite number.
Hence, option (b) is the correct answer.

Note:
One may note the fact that 2 is the smallest prime number and 4 is the smallest composite number. You must remember the definitions of these numbers to solve the question. You may note that every natural number is either a prime or composite number except 1. This is because 1 has only one factor, i.e. the number itself 1.