Having learnt about factors of numbers, we will learn about another classification of numbers on the basis of factors. This is classification of numbers as prime and composite numbers. Before we try to know about this concept, let us recall factors. Factors of a number are the numbers which divide the given number completely or we can say that if a number is completely divisible by some other number, then the latter is called the factor of the former number. It is also important to note here that any number is always completely divisible by 1 & itself.
Turning to our topic of discussion here, let us define prime and composite numbers.
A number which has exactly two factors is called prime number. Such numbers are completely divisible by 1 & itself only, no other number completely divides such numbers. If we take 5 & list its factors, we get only 2 factors of 5, viz.,1 & 5; so 5 is a prime number. Similarly, 2, 3, 7, 11, 13, 17,19, 23, 29,etc are all prime numbers.
A number which has at least 3 factors, i.e., other than 1 & itself, it is divisible by at least 1 other number is called a composite number. If we take 4 & list its factors, we get 3 factors of 4, viz.,1 , 2 & 4 itself; so 4 is a composite number. Similarly, 6, 8, 9, 10, 12, 14, 16, etc are composite numbers.
In listing the examples of prime & composite numbers, we notice that our numbers begin with 2; not 1. It is because 1 is the only number which has only 1 factor, i.e.,1. It is 1 itself, hence, it does not fit either of the definitions of prime or composite numbers. Thus, we say that 1 is neither prime nor composite.
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Turning to our topic of discussion here, let us define prime and composite numbers.
A number which has exactly two factors is called prime number. Such numbers are completely divisible by 1 & itself only, no other number completely divides such numbers. If we take 5 & list its factors, we get only 2 factors of 5, viz.,1 & 5; so 5 is a prime number. Similarly, 2, 3, 7, 11, 13, 17,19, 23, 29,etc are all prime numbers.
A number which has at least 3 factors, i.e., other than 1 & itself, it is divisible by at least 1 other number is called a composite number. If we take 4 & list its factors, we get 3 factors of 4, viz.,1 , 2 & 4 itself; so 4 is a composite number. Similarly, 6, 8, 9, 10, 12, 14, 16, etc are composite numbers.
In listing the examples of prime & composite numbers, we notice that our numbers begin with 2; not 1. It is because 1 is the only number which has only 1 factor, i.e.,1. It is 1 itself, hence, it does not fit either of the definitions of prime or composite numbers. Thus, we say that 1 is neither prime nor composite.
You can learn about distance formula calculator from different sites online. Also to know about Indian certificate of secondary education, you can search it online.
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