Class 6 Chapter 3 Playing with Numbers
Ncert Solution Class 6th Maths Chapter 3
Class 6 Chapter 3 Playing with Numbers  Ncert Solutions for Class 6 Maths Chapter 3 Playing with Numbers by Online Shiksha
Chapter 3 Playing with Numbers – Exercise 3.1
1. Write all the factors of the following numbers:
(a) 24 (b) 15 (c) 21 (d) 27 (e) 12 (f) 20 (g) 18 (h) 23 (i) 36
A product is obtained by multiplying two whole numbers. The multiplied numbers are the product’s factors. A factor, on the other hand, completely divides a number without leaving any remainder.
 Factors of 24 = 1, 2, 3, 4, 6, 12, 24
 Factors of 15 = 1, 3, 5, 15
 Factors of 21 = 1, 3, 7, 21
 Factors of 27 = 1, 3, 9, 27
 Factors of 12 = 1, 2, 3, 4, 6, 12
 Factors of 20 = 1, 2, 4, 5, 10, 20
 Factors of 18 = 1, 2, 3, 6, 9, 18
 Factors of 23 = 1, 23
 Factors of 36 = 1, 2, 3, 4, 6, 9, 12, 18, 36
2. Write first five multiples of: (a) 5 (b) 8 (c) 9
Multiples – Multiples are the results of multiplying a number by an integer.
 First five multiples of 5 are 5, 10, 15, 20, 25.
 First five multiples of 8 are 8, 16, 24, 32, 40.
 First five multiples of 9 are 9, 18, 27, 36, 45.
3. Match the items in column 1 with the items in column 2:
Column 1  Column 2 
(i) 35  (a) Multiple of 8 
(ii) 15  (b) Multiple of 7 
(iii) 16  (c) Multiple of 70 
(iv) 20  (d) Factor of 30 
(v) 25  (e) Factor of 50 
(f) Factor of 20 
Answers –
I – b , ii – d , iii – a , iv – f , v – e
4. Find all the multiples of 9 up to 100.
Multiples of 9 up to 100 – 9, 18, 27, 36, 45, 54, 63, 72, 81, 90, 99
9*1=9 , 9*2 = 18 , 9*3 = 27 , 9*4 = 36 ,9*5=45 , 9*6=54 , 9*7 =63 ,9*8 = 72 ,9*9 = 81 , 9*10=90 , 9*11 = 99
Chapter 3 Playing with Numbers – Exercise 3.2
What is the sum of any two –
Odd numbers.
The sum of any two odd numbers is an even number. Example: 1 + 3 = 4, 3 + 5 = 8, 5+7= 12 , 7+9 = 16 , 9+11 = 20 , 11+13=14 ans so on….. Even numbers. The sum of any two even numbers is an even number. Example: 2 + 4 = 6, 4+6 = 10 , 6 + 8 = 14 , 8+10=18 , 10+12=22 , 12+14 = 26 and so on……….. 
State whether the following statements are true or false

The numbers 13 and 31 are prime numbers. Both these numbers have same digits 1 and 3.Find such pairs of prime numbers up to 100.

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

What is the greatest prime number between 1 and 10?
Ans – 7
Express the following as the sum of two odd numbers:

Give three pairs of prime numbers whose difference is 2.
[Remark: Two prime numbers whose difference is 2 are called twin primes.]

Which of the following numbers are prime:
(a) 23 (b) 51 (c) 37 (d) 26
23 and 37 are prime [51 and 26 can be divided by 17 and 13]
Write seven consecutive composite numbers less than 100 so that there is no prime number between them.
90, 91, 92, 93, 94, 95, 96 – there is no prime numbers between these numbers.
Express each of the following numbers as the sum of three odd primes – (a) 21 (b) 31 (c) 53 (d) 61
 21 = 3+7+11
 31 = 3+11+17
 53 = 13+17+23
 61=19+29+13
Write five pairs of prime numbers less than 20 whose sum is divisible by 5. [Hint: 3 + 7 = 10]
2+3 , 3+7 , 7+13 , 3+17 , 2+13
Fill in the blanks:
(a) A number which has only two factors is called a _______________.
(b) A number which has more than two factors is called a _______________. (c) 1 neither _______________ nor _______________. (d) The smallest prime number is _______________. (e) The smallest composite number is _______________. Pages: 1 2
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