Factors of a Number

Q.

HCF of two numbers is always a factor of their LCM.

1. True
2. False

Q.

If a number is divisible by both 2 and 3, then it is divisible by

1. 5

2. 6

3. 7

4. 8

Q. The sum of two consecutive odd numbers is always divisible by:

1. 1
2. 2
3. 4
4. All of the above

Q. 1 is the only number having exactly one factor.

1. False
2. True

Q.

How to calculate HCF and LCM of Fractions

Q.

If a number is divisible by two co-prime numbers, then it is also divisible by their

1. sum

2. difference

3. product

4. quotient

Q.

What are the factors of $216$ and $215$?

Q.

Can two numbers have 16 as their HCF and 204 as their LCM? Give reason

Q.

What do you mean by factors?

Q. What fraction of the first 10 natural numbers are prime numbers?

1. 2/5
2. 1/4
3. 1/5
4. 2/3

Q.

All natural numbers are divisible by 1.

1. True

2. False

Q.

Find the H.C.F of 24, 32, and 36.

1. 4

2. 2

3. 3

4. 1

Q.

If $a$, $b$, $c$ and $d$ are distinct prime numbers where $a$ is the smallest prime, then $a\times b\times c\times d$ is

1. Odd number

2. Even number

3. Prime number

4. 1

Q. The ratio of two numbers is 3:4 and their HCF is 4. Their LCM is

(a) 12
(b) 16
(c) 24
(d) 48

Q. When we divide -144 by -16, we will get -9 as a quotient.

1. True
2. False

Q.

Find Hcf and lcm by using the property

27, 90

145, 232

Q.

What is the HCF and LCM of 175, 1225 and 3675 ?

Q.

Find the common factors of

$16$ and $18$

Q. The common factors of 12 and 20 are 1, 2 and 4. The greatest common factor of them is 4

1. True
2. False

Q.

Using prime factorisation method, find HCF nad LCM of $36$ and $120$.

Q.

The difference between the sum of prime numbers from $21$ to $30$ and the sum of composite from $21$ to $30$ is divisible by which of the following numbers?

1. $3$

2. $7$

3. $151$

4. $17$

Q. What are the common factors of 75, 60 and 210?

1. 1, 3, 5 and 15

2. 1, 3, 5, 15 and 25

3. 1, 3, 15 and 25

4. 3, 6 and 15

Q. What is the lcm and hcf of 36, 96, 72

Q.

A number $a$ has 7 as its smallest prime factor, and another number $b$ has 3 as its smallest prime factor. What is the smallest prime factor of the number $a+b$?

1. 3

2. 2

3. 7

4. 5

Q.

7 consecutive composite numbers less than 100 are:

1. 81, 82, 83, 84, 85, 86, 87

2. 90, 91, 92, 93, 94, 95, 96

3. 65, 67, 68, 69, 70, 71, 72

4. 46, 47, 48, 49, 50, 51, 52

Q.

Find at least $10$ pairs of co-primes from the given numbers.

$12,15,27,36,17,25,32,49,111,121,13$.

Q. If the HCF of two number is 16 and their product is 3072, then their LCM is

(a) 182
(b) 192
(c) 12
(d) None of these

Q.

If a number is divisible by 4, then it must be divisible by 8.

1. True

2. False

Q. Which of the following is/are common factor of $144\&169$?

1. $11$
2. $48$
3. $36$
4. 1

Q.

$25$ is an odd number but it is not a prime number

1. True
2. False