Prime and Composite Numbers

Q.

What are prime triplets

Q.

Question 5

What is the greatest prime number between 1 and 10?

Q. How many prime numbers are there between 1 to 20?

1. 6
2. 5
3. 7
4. 8

Q.

A boy was asked to find the LCM of 3, 5, 12 and another number.But while calculating, he wrote 21instead of 12and yet came with the correct answer. what could be the fourth number?

Q.

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

Q. Which one of the following statements is false?

1. If a number is divisible by two Co-Prime Numbers, then it is also divisible by the product of those Co-Prime Numbers.
2. 2 is the only even and the smallest prime number.
3. Every number (except 1 and 2) will have at least 3 factors.
4. Prime Factorisation means using only Prime Numbers to write the Factors of a number.

Q.

A number that has more than two factors is called a

1. Prime Number

2. Co-prime Number

3. Composite Number

4. None of these

Q.

Find the LCM of $40,42,45.$

Q. Is zero a prime or composite number

Q.

Write seven consecutive composite numbers less than $100$ so that there is no prime number between them.

Q.

Question 12 (c)

Fill in the blanks:

1 is neither ______ nor ___________.

Q.

What is the composite number between $20\text{and}40$ ?

Q.

A number for which sum of all its factors is equal to twice the number is called a ________.

1. Perfect number

2. Prime Number

3. Composite Number

4. Even number

Q.

Is $8128$ a perfect number?

Q. If $a$ and $b$ are two distinct prime numbers, then the Highest Common Factor of $a$ and $b$ is

1. $a\times b$
2. 1
3. 2
4. 0

Q.

Write composite number between $40$ and $50$.

Q.

Number of prime numbers between $50$ to $60$ is:

1. $2$

2. $3$

3. $4$

4. $1$

Q.

Two prime numbers whose difference is $2$ are called?

Q.

During a sale, colour pencils were being sold in packs of $24$ each and crayons in packs of $32$ each. If you want full packs of both and the same number of pencils and crayons, how many each would you need to buy?

Q.

Question 2 (i)

State whether the following statement is true or false:

All even numbers are composite numbers.

Q. Write all the prime numbers between 1 and 100. How many are there?

Q.

Write the following numbers as a product of two co-prime numbers .

$143$

Q. All even numbers greater than 2 are composite numbers.

1. True
2. False

Q.

How many composite numbers are there between $60$ and $90?$

Q. The smallest factor of a number is 1, and the largest factor of a number is the number itself.

1. False
2. True

Q.

What is the greatest prime number between 1 and 10?

Q.

Write the largest prime number between 150 and 170

Q.

Composite numbers have more than _______ factors.

1. 6

2. 10

3. 15

4. 2

Q.

Express the product of prime factors of 230 and 272

Q. Write all prime numbers between:

(i) 10 and 50
(ii) 70 and 90
(iii) 40 and 85
(iv) 60 and 100