Teacher's Resources

3. Playing with Numbers

Click the correct answer (True & False).

A number divisible by 3 is also divisible by 6.

True

False

The numbers 8 and 9 are factors of 72.

True

False

Two consecutive prime numbers which are odd are called twin primes.

True

False

There is only one composite number between two primes.

True

False

Twin primes are consecutive odd numbers.

True

False

There is only one composite number between twin primes.

True

False

Two co-prime numbers are always prime.

True

False

Prime factorization of 12 is equal to 1 × 2 × 2 × 3.

True

False

A factor of a number is an exact divisor of the number.

True

False

Two numbers having only 1 as the common factor are called co-prime numbers.

True

False

Click the correct answer.

Which of the following numbers is a perfect number?

Which of the following numbers is divisible by 4?

25,13,784

18,20,741

70,12,345

68,54,321

What is the least value of * so that the number 9274*5 is divisible by 9?

Which of the following is divisible by 11?

11,11,111

11,22,222

3,33,33,333

44,44,444

What is the least value of * so that the number 25*215 is divisible by 3?

What is the purpose of using the method of Sieve of Eratosthenes?

To find perfect numbers

To find prime numbers

To find twin primes

To find co-primes

If the LCM of two numbers is 30, then which of the following cannot be their HCF?

What are the first three multiples of 7?

7, 14 and 21

7, 15 and 23

7, 17 and 29

14, 21 and 28

What is the smallest factor of 64?

Which is the smallest odd prime number?

Click each box on the left and also click on the matching box of the right.

Match to complete the statements.

35 is a

15 is a

16 is a

20 is a

25 is a

multiple of 7

factor of 30

multiple of 8

factor of 20

factor of 50

Click the correct answer.

The numbers 17 and form a pair of twin primes.

A number is divisible by if the number formed by its last two digits is divisible by it.

Two prime numbers are called primes if the difference between them is 2.

even

twin

odd

A number is called the sum of its factors, except itself, is greater than the number.

abundant

even

prime

The whole number can never be a divisor.

The smallest prime number is .

The smallest composite number is .

The smallest even natural number is .

Numbers having more than two factors are called .

composite numbers

twin primes

prime numbers

BACK