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\\December 6, 2023 12:53 PM Surender Prajapati Proof 5 Reader _________________________ Date: ___________________74

Numbers which have more than two factors are called composite numbers.

Finding Prime Numbers or composite Numbers

To find whether a number is a prime number or a composite number, we first check
whether it is an even number or an odd number, as every even number other than

2 is a composite number.

If the number is odd, divide it by prime numbers 3, 5, 7, 11 and so on. Continue the

division till the quotient becomes less than the divisor..

example 1: Is 39 a prime number?

Solution: 39 is not divisible by 2 because it is not an even number. But, 39 is

divisible by 3 because 3 + 9 = 12, which is divisible by 3.

Thus, 39 is a composite number.

example 2: Is 65 a prime number?

Solution: 65 is not divisible by 2 because it does not end with even digit. 65 is not

divisible by 3 because 6 + 5 = 11 is not divisible by 3.

65 is divisible by 5 because it ends with 5.

Thus, 65 is not a prime number, it is a composite number.

example 3: Is 89 a prime or composite number?

Solution: Since, 89 is not an even number. So, it is not divisible by 2.

8 + 9 = 17, 17 is not divisible by 3. 7 89 12 Q
7
So, 89 is not divisible by 3. 19

89 is also not divisible by 5. 14
5 R
Divide 89 by 7, we get the remainder 5.

So, 89 is not divisible by 7.

Further, divide 89 by 11, we get the remainder 1.

89 is not divisible by 11. 11 89 8 Q

Further, division is not required as the quotient 8 is less than 88 R
1
the divisor 11.

Thus, 89 is a prime number.

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