Playing with numbers Ex-3.2
NCERT solutions for Maths Playing with numbers
NCERT Solutions for Class 6 Maths Playing with numbers
Class –VI
Mathematics (Ex. 3.2)
Question1. What is the sum of any two:
(a)Odd numbe
(b)Even numbe
Answer:
(a) The sum of any two odd numbers is an even number.
Example: 1 + 3 = 4, 3 + 5 = 8
(b) The sum of any two even numbers is an even number.
Example: 2 + 4 = 6, 6 + 8 = 14
Question 2. State whether the following statements are true or false:
(a)The sum of three odd numbers is even.
(b)The sum of two odd numbers and one even number is even.
(c)The product of three odd numbers is odd.
(d)If an even number is divided by 2, the quotient is always odd.
(e)All prime numbers are odd.
(f)Prime numbers do not have any facto
(g)Sum of two prime numbers is always even.
(h)2 is the only even prime number.
(i)All even numbers are composite numbe
(j)The product of two even numbers is always even.
Answer:
(a) False, (b) True, (c) True, (d) False, (e) False, (f) False,(g) False, (h) True, (i) False, (j) True
NCERT Solutions for Class 6 Maths Exercise 3.2
Question 3.The numbers 13 and 31 are prime numbe Both these numbers have same digits 1 and 3. Find such pairs of prime numbers up to 100.
Answer: 17 and 71; 37 and 73; 79 and 97
Question 4.Write down separately the prime and composite numbers less than 20.
Answer:
Prime numbers: 2, 3, 5, 7, 11, 13, 17, 19
Composite numbers: 4, 6, 8, 9, 10, 12, 14, 15, 16, 18
NCERT Solutions for Class 6 Maths Exercise 3.2
Question 5.What is the greatest prime number between 1 and 10?
Answer: The greatest prime number between 1 and 10 is ‘7’.
Question 6.Express the following as the sum of two odd numbers:
(a) 44
(b) 36
(c) 24
(d) 18
Answer:(a) 3 + 41 = 44, (b) 5 + 31 = 36, (c) 7 + 17 = 24, (d) 7 + 11 = 18
Question 7.Give three pairs of prime numbers whose difference is 2.
[Remark: Two prime numbers whose difference is 2 are called twin primes.]Answer:
3 and 5;
5 and 7;
11 and 13
NCERT Solutions for Class 6 Maths Exercise 3.2
Question 8.Which of the following numbers are prime:
(a) 23
(b) 51
(c) 37
(d) 26
Answer: (a) 23 and (c) 37 are prime number
Question 9.Write seven consecutive composite numbers less than 100 so that there is no prime number between them.
Answer: 90, 91, 92, 93, 94, 95, 96
NCERT Solutions for Class 6 Maths Exercise 3.2
Question 10.Express each of the following numbers as the sum of three odd primes:
(a) 21
(b) 31
(c) 53
(d) 61
Answer: (a) 21 = 3 + 7 + 11, (b) 31 = 3 + 11 + 17 , (c) 53 = 13 + 17 + 23, (d) 61 = 19 + 29 + 13
Question 11.Write five pairs of prime numbers less than 20 whose sum is divisible by 5.
[Hint: 3 + 7 = 10]Answer: 2 + 3 = 5;, 7 + 13 = 20;, 3 + 17 = 20;, 2 + 13 = 15;, 5 + 5 = 10
NCERT Solutions for Class 6 Maths Exercise 3.2
Question 12. 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 _______________.
(f)The smallest even number is _______________.
Answer: (a) Prime number, (b) Composite number, (c) Prime number and composite number, (d) 2, (e) 4, (f) 2