Prime Numbers

Q. Find the greatest number of 5 digits exactly divisible by 9, 12, 15, 18 and 24

Q.

Write all the prime numbers less than $10.$

Q.

How many prime numbers are there between $100$ to $200$?

Q.

Make a list of seven consecutive numbers, none of which is prime.

Q.

The numbers $13$‘ and ’$31$‘ are prime numbers. Both these numbers have the same digits ’$1$‘and ’$3$‘. Find such pairs of prime numbers up to ’$100$.

Q.

What is a prime number between $10$ and $20$?

Q.

Which is the smallest odd prime number? $1or3$

Q. Is 91 a prime number

Q.

Why is $2$ the only even prime number?

Q.

How many odd prime numbers are there between $1$ to $100$ ?

Q.

Write all prime numbers between $60$ and $80$.

Q. Which of the following is smallest prime number?

1. 0
2. 1
3. 2
4. 3

Q.

What is a prime number between $40$and $50$?

Q.

Write the set of even prime numbers from $1$ to $50$.

Q. Express each number as a product of its prime factors:
(i) $140$ (ii) $156$ (iii) $3825$

Q. Find the number of factors of 500.

Q.

How many prime numbers lie between 1 and 40?

1. 21
2. 13
3. 12
4. 11

Q.

Question 25
Sum of the number of primes between 16 to 80 and 90 to 100 is

(A) 20
(B) 18
(C) 17
(D) 16

Q.

Question 2 (f)

State whether the following statement is true or false:

Prime numbers do not have any factors.

Q.

A number which has only two factors is called a

________________________________________

Q.

Write true or false. 1 is the smallest prime number?

Q.

All even numbers are composite numbers

1. True
2. False

Q.

Question 2 (h)

State whether the following statement is true or false:

2 is the only even prime number.

Q.

Express the composite numbers as the sum of two prime numbers -:

$30=.................+..................$

Q.

How many prime numbers are there from $1to30$? Write all the prime numbers.

Q.

Express $30$ as a sum of two odd primes

Q.

Question 6 (d)

Express the following as the sum of two odd primes:
18

Q.

Find the sum of the place values of two odd digits in 6, 34, 568.

Q. What is Perfect numbers ​​​​​?

Q.

Question 12 (a)

Fill in the blanks:

A number which has only two factors is called a ________.