MCQ Questions for Class 6 Maths Playing With Numbers Quiz 1

Identify the prime number among the following options.

0%
$11$
0%
$15$
0%
$18$
0%
$20$

Explanation

$11$ is a prime number because it has only two factors that are

$1$ and

$11$ .

So, option A is correct.

Addition of prime number

0%
gives a prime number
0%
gives a composite number
0%
may give a prime number or composite number
0%
none of these

Explanation

$2$ and

$3$ are prime numbers

$7$ and

$5$ are prime numbers

$2 + 3 = 5$ (prime) but

$7 + 5 = 12$ (composite).

So, option C is correct.

Which of the following is the factor of all prime numbers?

0%
$1$
0%
$2$
0%
$3$
0%
$4$

Explanation

Option

$A$ is correct because

$1$ is the factor of all prime numbers.

State true or false:
A number and its successor are always co-primes.

0%
True
0%
False

The total number of prime numbers between

$120$ and

$140$ is

0%
$7$
0%
$6$
0%
$5$
0%
$4$

Explanation

The prime numbers must be from the odd numbers between

$120$
and

$140$ .
The prime numbers are

$127, 131, 137, 139$ .
Therefore, there are 4 prime numbers between

$120$ and

$140$ .

Which of the following is not a prime number ?

0%
5
0%
7
0%
8
0%
11

Which of the following is not a composite number?

0%
$4$
0%
$6$
0%
$7$
0%
$8$

An integer which is not divisible by 2 is called a/an

0%
even number
0%
odd number
0%
prime number
0%
composite number

The units digit of every prime number (other than

$2$ and

$5$ ) must be necessarily

0%
$1, 3$ or $5$
0%
$1, 3, 7$ or $9$
0%
$7$ or $9$
0%
$1$ or $7$

Explanation

All even numbers (other than

$2$ ) are composite, so prime numbers cannot end with any of the digits

$0,2,4,6,8$ .

Also, a number with unit digit

$5$ will be divisible by

$5.$

Therefore, the unit's digit of every prime number(other than

$5$ ) must be necessarily

$1, 3, 7$ or

$9$ .

Which of the following is not a composite number?

0%
$352+6$
0%
$357+7$
0%
$352+7$
0%
$353+1$

Explanation

$A:$

$352+6 = 358$ which is even, and have factors other than

$1$ and itself, So it is a Composite number.

$B:$

$357+7 = 364$ which is even, and have factors other than

$1$ and itself, So it is a Composite number.

$C:$

$352+7 = 359$ which is odd, and does not have factors other than

$1$ and itself, So it is a Prime number.

$D:$

$353+1 = 354$ which is even, and have factors other than

$1$ and itself, So it is a Composite number.

Hence, option

$C.$

Every composite number can be expressed (factorised) as a product of primes, and this factorisation is unique apart from the order in which the prime factors occur.

0%
True
0%
False
0%
Neither
0%
Either

Explanation

This is true as any composite number can be expressed in terms of its prime factors. The prime factors for 2 numbers can be same but their combination is unique.
Example,

$12=2^2*3$ and

$18=2*3^2$
Both have prime factors as 2 and 3 but the combination that 12 has is different from that of 18.

The number of composite numbers between

$101$ and

$120$
(excluding both) are

0%
$11$
0%
$12$
0%
$13$
0%
$14$

Explanation

There are

$9$ even numbers which are all composite numbers.
Amongst the odd numbers

$105, 111, 115, 117, 119$ are composite numbers.
So, there are

$14$ composite numbers in the given range.

The value of

$\textit x$ in the factor tree is : (Blank Boxes has Multiplication symbol.)

0%
$30$
0%
$150$
0%
$100$
0%
$50$

Explanation

$3\times 2=6$

$6\times 5=30$

$30\times 5=150$

Correct answer will be option B

A number other than one which is either divisible by

$1$ or itself is called a

0%
composite number
0%
prime number
0%
comprime number
0%
none of these

Explanation

Given that a number is divisible by itself and $1$ .
$\therefore$ If x is the number then its factors are x and $1$ . So this fits in the condition for a number to be prime.
$\therefore$ It is a prime number.

Which of the following numbers have most number of divisors?

0%
$176$
0%
$182$
0%
$99$
0%
$101$

Explanation

If a number has

$n$ number of factors, it will have

$n$ divisors.

The given numbers are

$176, 182, 99, 101.$

$176={ 2 }^{ 4 }\times 11\Rightarrow 5$ factors

$182=2\times 7\times 13\Rightarrow 3$ factors

$99=3\times 3\times 11\Rightarrow 3$ factors

$101=1\times 101\Rightarrow 1$ factor

$\therefore 176$ has greatest number of factors.

Write three pairs of co-primes between

$15$ and

$30.$

0%
$19$ and $23, 23$ and $25,$ & $27$ and $29$
0%
$16$ and $21, 18$ and $25,$ & $20$ and $27$
0%
$16$ and $22, 18$ and $26,$ & $20$ and $27$
0%
none of these

Explanation

Two integers

$a$ and

$b$ are said to be relatively prime, mutually prime, or co-prime if the only positive integer that evenly divides both of them is

$1.$ That is, the only common positive factor of the two numbers is

$1.$
They are

$16$ and

$25, 27$ and

$20, 21$ and

$22.$

Say true or false:

$45$ has

$11$ as a factor.

0%
True
0%
False

Explanation

Factors of

$45 = 1, 3, 5, 9, 15$ and

$45$

Which of the following is a prime number?

0%
$889$
0%
$997$
0%
$899$
0%
$1147$

Explanation

A prime can be written as

$6k+1$ or

$6k-1$ provided the number is greater than

$6$ .

$997=166*6+1$
Therefore,

$997$ is a prime number.

The number of prime numbers between 0 and 20 is

0%
7
0%
8
0%
6
0%
9

Explanation

The prime numbers between

$0$ and

$20$ are

$2, 3, 5, 7, 11, 13, 17$ and

$19$ .
Hence, the number of prime numbers between

$0$ and

$20$ is

$8$ .

Write all prime numbers between

$20$ and

$50.$

0%
$21, 29, 33, 37, 41, 43$ and $47$
0%
$29, 33, 37, 39, 41, 43$ and $47$
0%
$23, 29, 31, 37, 41, 43$ and $47$
0%
None of these

Explanation

All prime numbers between

$20$ and

$50$ are

$23, 29, 31, 37, 41, 43$ and

$47.$

Say true or false:

$24$ is factor of

$48$

0%
True
0%
False

Explanation

$48=24\times 2$

As can be observed from the above multiplication, we can say that

$24$ is a factor of

$48$ .

The number which is neither prime nor composite is

0%
$3$
0%
$1$
0%
$2$
0%
$5$

Explanation

A prime number is a number which has only two factors,

$1$ and the number itself. So, a prime number has 2 factors.

A composite number is a number that has factors other than

$1$ and the number itself. A composite number has more than 2 factors.

The number which is neither prime nor composite is

$1$ as it is divisible only by

$1$ . It has only one factor.

Hence, Option B is correct answer.

What is the remainder obtained when a prime number greater than

$6$ is divided by

$6$ ?

0%
$1 \ or\ 3$
0%
$1 \ or\ 5$
0%
$3\ or\ 5$
0%
$4 \ or\ 5$

Explanation

We can take an example. Prime numbers greater than $6$ are $7, 11, 13,$ and so on. When $7$ is divided by $6,$ remainder is $1$ . When $11$ is divided by $6$ , remainder is $5$ . Similarly, when $13$ is divided by $6$ , remainder is $1$ . The remainder obtained is either $1$ or $5$ .

So the correct answer will be option $B$

Common factors of

$9$ and

$36$ are

0%
$1,3,9$
0%
$1,4,3,5,9$
0%
$1,4,5$
0%
none of these

Explanation

Factors of

$9 = 1, 3, 9$
Factors of

$36 = 1, 3, 4, 6, 9, 12, 36$

Common factors are

$1, 3, 9$

The numbers which have more than two factors are called

0%
even
0%
prime
0%
composite
0%
none of these

The two numbers which have only

$1$ as their common factor are called as ____ .

0%
co-primes
0%
twin prime
0%
composite
0%
none of these

Explanation

The two numbers which have only 1 as their common factor are called co-primes.

For example, Factors of

$5$ are

$1, 5$
Factors of

$3$ are

$1, 3$

Common factors is

$1$ .
So they are co-prime numbers.

A number is divisible by

$6$ , when it is divisible by both _____ .

0%
$4$ and $3$ .
0%
$2$ and $4$ .
0%
$2$ and $3$ .
0%
$3$ and $5$ .

Explanation

$2 \times 3 = 6$
A number is divisible by 6 if it is divisible by both

$2 , 3$

A number is divisible by

$8$ , if the number formed by the digits in ______ places is divisible by

$8$ .

0%
units and tens
0%
tens and hundreds
0%
units
0%
units, tens and hundreds

Explanation

A number is divisible by

$8$ , if the number formed

by the digits in units, tens and hundreds place is

divisible by

$8$ .

So, option D is correct.

H.C.F. of

$36$ and

$144$ is equal to :

0%
$36$
0%
$144$
0%
$4$
0%
$2$

Explanation

Factors of

$36 = 2,2,3,3$
Factors of

$144 = 2,2,2,2,3,3$
Common factors of

$36$ and

$144$ are

$2,2,3,3$

$\therefore H.C.F = 2\times 2\times 3\times 3 = 36$
Option A is correct.

How many prime numbers are there between

$0$ and

$30$ ?

0%
$9$
0%
$10$
0%
$8$
0%
$11$

Explanation

Prime numbers:- The numbers which are divisible by

$1$ and themselves, or the number which has only two factors,

$1$ and the number itself

e.g.

$7$

Note:-

$1$ is not a prime number, the smallest prime number is

$2$

Prime numbers between

$1$ and

$30$ are

$2,~3,~5,~7,~11,~13,~17,~19,~23,~29.$

Total ten numbers are there.

CBSE Questions for Class 6 Maths Playing With Numbers Quiz 1 - MCQExams.com

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Practice Class 6 Maths Quiz Questions and Answers

CBSE Questions for Class 6 Maths Playing With Numbers Quiz 1 - MCQExams.com

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Practice Class 6 Maths Quiz Questions and Answers

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