Factors

Q.

Question 1 (a)

Find the common factors of:
20 and 28

Q.

Find the factors of $288$.

Q.

Write down separately the prime and composite numbers less than $20$.

Q.

Question 2 (b)

Find the common factors of:
15 and 25

Q.

Whats the Lowest Common Multiple (LCM) of $12$ and $15$?

Q.

Three different containers contain 403 L , 434L , 465 L, of milk respectively. Find the capacity of a container which can measure the milk of all the containers in an exact number of times .

Q. is a factor of every number and every number is a factor of .

1. 1
2. itself
3. 2
4. next number

Q.

If two numbers are co-primes, at least one of them must be prime.

1. True

2. False

Q.

A and B are two positive integers such that AB=64.Which of the following is not the correct value of A+B?

a) 65 b) 35

c) 16 d) 20

Q. Which is the missing number in the following factor tree?

1. 2
2. 3
3. 4
4. 12

Q.

Which number is the only even prime number?

1. $0$

2. $2$

3. $4$

4. $6$

Q.

A number which is divisible by only 1 and the number itself is called ________.

1. an even number

2. an odd number

3. a prime number

4. a composite number

Q.

What is the factorial of $20$?

Q.

Find the HCF of the two numbers 132 and 165.

1. 37

2. 39

3. 33

4. 34

Q.

Two numbers having _____ as the only common factor are called ________ numbers.

1. 2, twin prime

2. 2, co-prime

3. 1, co-prime

4. 1, twin prime

Q.

Two numbers having '1' as the only common factor are called ___ numbers.

Q.

The LCM of 18, 24 & 32 is _______.

1. 288

2. 32

3. 24

4. 432

Q. Find the smallest no. which when divided by 28 and 32 leaves remainder 8 and 12.

Q.

Question 6 (c)

Express the following as the sum of two odd primes:
24

Q.

5 and 12 are co-prime numbers.

1. True

2. False

Q.

Every factor of a number is an exact ___ of that number.

Q.

List all composite numbers from

$31$ to $50$

Q. Find the prime numbers from the following.

30, 31, 32, 33, 34, 35, 36, 37, 38, 39.

1. 32 and 39
2. 30 and 34
3. 31 and 37
4. 35 and 37

Q.

Three brands A, B and C of biscuits are available in packets of 12, 15, and 21 biscuits respectively.
If a shopkeeper wants to buy an equal number of biscuits of each brand, then what is the minimum number of packets of each brand he should buy? [4 MARKS]

Q.

Write the first six multiples of:

$8$

Q.

Write the first six multiples of:

$6$

Q. Express the greatest 2-digit number as a product of its prime factors.

Q. From the choices given below, mark the co-prime numbers.

1. 2, 110
2. 10, 20
3. 9, 24
4. 4, 5

Q.

From the numbers 2, 3, 4, 5, 6, 7, 8, 9 how many pairs of co- primes can be formed and how ?

Q. Which of the following is a pair of co-prime numbers?

1. 6, 9
2. 4, 7
3. 5, 10
4. 4, 8