Are you looking for Number Systems Extra Questions and Answers, if yes? then you the right place. Here we are providing Number Systems Extra Questions and Answers Class 9 Maths Chapter 1.
Number Systems Extra Questions and Answers Maths Chapter 1
- 1 mark question
1) 0 is a ……… Number.
a) Natural number
b) irrational number
c) Rational number
d) whole number
Ans-c
2) A rational and irrational number of product is…..
a) always irrational and rational number
b) only rational number
c) Always an irrational number
d) only natural number
Ans-c
3) The decimal representation of 7/18 is….
a) 0.333333
b) 0.3888889
c) 3.88888
d) 0
Ans-b
4) √22 is a rational number?
=> √22 is not rational number, because it is a non terminating.
5) Every natural number is whole number?
a) true
b) false
Ans=> true, because zero is not natural number but also it is not whole number.
6) C is denoted as a……….. Number.
a) Rational number
b) Natural number
c) integer
d) whole number
Ans-a
7) All irrational number are…………. Number.
a) Whole number
b) irrational number
c) rational number
d) Natural number
Ans-b
8) Integer number set is denoted by…..
a)W
b) N
c)Z
d) Q
Ans- Z
9) 0.399999…. is a….. Number.
a) Natural number
b) whole number
c) Rational number
d) irrational number
Ans- c
10) Which of the following number is an irrational number?
a) √25
b) √16
c) √12
d) √9
Ans-c
11) A number s is called a irrational number, if it cannot be written in the form ……
a) p×q
b) p/q
c) p+q
d) p-q
Ans-b
12) A number r is called as………..
a) rational number
b) irrational number
c) natural number
d)None of these
Ans-a
13) All the rational and irrational numbers make up the collection of real number.
a) true
b) false
Ans-a
14) Define Rational Numbers.
Ans – A number ‘r’ is called a rational number if it can be written in the form p/q, where p and q are integers and q ≠ 0.
15) define Natural Numbers.
Ans- Numbers which start from one (1) are known as natural numbers. The collection of all natural numbers is denoted by N.
N = {1, 2, 3, 4, …….}
- 2 marks question
1) Simplify
a) 3^3/2•3^1/2
=> =3^[3/2+1/2]
=3^[4/4]
=3^1
=3
b) [4^1/4]3
=> =[4^1/4]3
=4^3/4
2) Simplify the following expansion.
a) (3+√3) (3-√3)
=> =3^2-(√3) ^2
=9-3
=6
b) (√9-√4) (√9+√4)
=> =(√9) ^2-(√4) ^2
=9-4
=5
3) Classify the following numbers as rational Or irrational.
a) √22
=> it is an irrational number, because√22 is not it is a perfect square, so we can’t write 22 as a square of some number.
b)√ 225
=> it is a square of 15. it is a perfect square number, so √225 is an rational number.
4) Simplify
a) Multiply 4√5 by 3√5
=> =4×3×√5×√5
=12×5
=60
b) multiply 8√3 by 6√3
=> =8×6×√3×√3
=48×3
=144
5) Divide
a) 6√15÷4√3
=> =(6×√3) ÷√5
=3√5
b) Add 3√3+5√2 and √2-3√2
=> =(3√3+√2) +(5√2-3√2)
=((3+1)×√2) +((5+3) ×√3)
=4√2+2√3.
- 5 marks question
1) find the decimal expansion of 18/5, 6/9, 1/6
2) What can the maximum number of digits be in the repeating block of digits in the decimal expansion of 1/19? Perform the division to check your answer.
thus, 1/19 =0.0526315789…..
Therefore 1/19 has 10 digits in the repeating block of digits in the decimal expansion.
3) write the following rational numbers in decimal form:
a) 34/100
b) 237/500
c) 3×8/9
d) 5/6
e) 2/14
Solution:
3) Find:
1) (16) ^1/2
2) (225)^1/2
3) (625) ^1/2
4)(81) ^1/2
5)(121) ^1/2
Ans-
a) (16) ^1/2
=(4^2) ^1/2
=(4^1)
=4
b) (225) ^1/2
=(15^2) ^1/2
=(15^1)
=15
c) (625) ^1/2
=(25^2) ^1/2
=(25^1)
=25
d) (81) ^1/2
=(9^2) ^1/2
=(9^1)
=9
e) (121) ^1/2
=(11^2) ^1/2
=(11^1)
=11