What is a Prime Number ?
Prime number is a natural number greater than 1 that has no positive divisors other than 1 and the number itself
In other words, we can say prime numbers don’t have any factor other than 1 and itself.
For Example – 2, 3, 5, 7, 11, 13, 17, 19, 23, 29 are Prime Numbers.
Examples of Prime Numbers
Question 1
Which of the following is a prime number?
3, 6, 9
Explanation
Factors of 6 are 2 x 3 x 1
Factors of 3 are 3 x 1
Factors of 9 are 3 x 3 x 1
Here, Factors of 3 are 3 and 1
3 is not divisible by any other number, other than 1 and itself
Therefore, 3 is a prime number.
Question 2
Which of the following is a prime number?
10, 15, 5
Explanation
Factors of 10 are 2 x 5 x 1
Factors of 5 are 5 x 1
Factors of 15 are 3 x 5 x 1
Here, Factors of 5 are 5 and 1
5 is not divisible by any other number, other than 1 and itself
Therefore, 5 is prime number.
Question 3
Which of the following is a prime number?
26, 13, 30
Explanation
Factors of 26 are 2 x 13 x 1
Factors of 13 are 13 x 1
Factors of 30 are 3 x 5 x 2 x 1
Here, Factors of 13 are 13 and 1
13 is not divisible by any other number, other than 1 and itself
Therefore, 13 is a prime number.
Question 4
Which of the following is a prime number?
34, 17, 51
Explanation
Factors of 34 are 2 x 17 x 1
Factors of 17 are 17 x 1
Factors of 51 are 3 x 17 x 1
Here, Factors of 17 are 17 and 1
17 is not divisible by any other number, other than 1 and itself
Therefore, 17 is prime number.
Question 5
Which of the following is a prime number?
19, 38, 57
Explanation
Factors of 38 are 2 x 19 x 1
Factors of 19 are 19 x 1
Factors of 57 are 3 x 19 x 1
Here, Factors of 19 are 19 and 1
19 is not divisible by any other number, other than 1 and itself
Therefore, 19 is prime number.