Number System Class 9 MCQ Questions

Number System Class 9 MCQ Questions – Maths Class 9 MCQ Online Test are covered in this Article. Number System Class 9 MCQ Test contains 30 questions. Answers to MCQ on Number System Class 9 are available after clicking on the answer. MCQ Questions for Class 9 with Answers have been made for Class 9 students to help check the concept you have learnt from detailed classroom sessions and application of your knowledge.

Board CBSE
Textbook Maths (NCERT)
Class Class 9
Chapter Chapter 1 Number System
Category MCQ Questions for Class 9 Maths with Answers

Number System Class 9 MCQ with Answers

1. Every rational number is

(a)Whole number

(b)Real number

(c)Integer

(d)Natural number

Answer

Answer: (b)Real number


 

2. In between two rational numbers, there are

(a)No rational number

(b)one rational number

(c)two rational number

(d) infinite rational number

Answer

Answer: (d) infinite rational number


 

3.If a number cannot be written in p/q form, where p and q are integers and q≠0, then the number will be

(a)rational number

(b)irrational number

(c) both (a)and(b)

(d)None of these

Answer

Answer: (b)irrational number

Explanation: A number is called an irrational number, if it cannot be written in the form p/q, where p and q are integers and q≠0.


 

4. Three rational number between 2 and 3 are

(a)5/2, 6/2, 7/2

(b)11/5, 12/5, 13/5

(c) 11/6, 12/6, 13/6

(d)2/5, 3/5, 4/5

Answer

Answer: (b)11/5, 12/5, 13/5

Explanation: There are infinite rational numbers between 2 and 3

To find 3 rational numbers between 2 and 3, we need to multiply and divide both the number by 2+3=5

Hence, 2× (5/5) = 10/5 and 3× (5/5) = 15/5

So, three rational number between 2 and 3 are 11/5, 12/5 and 13/5.





5. √25 is a/an

(a)rational number

(b)irrational number

(c) neither rational nor irrational

(d)None of these

Answer

Answer: (a)rational number

Explanation: √25 = 5

So, √25 is a rational number.


 

6. The product of a rational and irrational number is always a/an

(a)integer

(b)rational

(c)irrational number

(d)None of these

Answer

Answer: (c)irrational number

Explanation: The product of a rational and irrational number is always an irrational number.


 

7. 3√2 + 7√2 is equal to

(a)6√2

(b)10√2

(c) 4√2

(d)5√2

Answer

Answer: (b)10√2

Explanation: 3√2 + 7√2 = √2(3+7) = 10√2


 

8. √a/b is equal to

(a)√ab

(b) √a√b

(c) (√a)/(√b)

(d) (√b)/(√a)

Answer

Answer: (c) (√a)/(√b)

Explanation: √(a/b)=(√a)/(√b)


 

9. Which of the following is an irrational number

(a)√25

(b) √4

(c)7.5

(d) √23

Answer

Answer: (d) √23

Explanation: √23=4.798=57315233….

The decimal expansion of the number is non terminating non recurring. Hence, it is an irrational number.


 

10. The decimal expansion of a number is terminating then the number is

(a)rational

(b)irrational number

(c)neither rational nor irrational

(d)None of these

Answer

Answer: (a)rational

Explanation: The decimal expansion of a number is terminating then the number is rational


 

Number System Class 9 MCQ with Answers

11. In between two rational numbers, there are

(a)No irrational number

(b)one irrational number

(c)infinite irrational number

(d)None of these

Answer

Answer: (c)infinite irrational number


 

12.The irrational number between 2 and 3 is

(a)√4

(b) √7

(c)√9

(d)√10

Answer

Answer: (b) √7

Explanation: Approximate value of √7 = 2.64

2.64 is between 2 and 3.


 

13. Addition of √5 + 7√3 and 3√5 -√3 is equal to

(a)4√5 + 6√3

(b) √5 + 5√3

(c) 3√5 + 6√3

(d) 3√5 + 7√3

Answer

Answer: (a)4√5 + 6√3

Explanation: (√5 + 7√3) + (3√5 -√3) = (√5 +3√5) +(7√3 -√3)

= (1+3) √5 + (7-1) √3

= 4√5 +6√3





14. 9√7× 9√7 is equal to

(a)567

(b)765

(c)81√7

(d) 9√7

Answer

Answer: (a)567

Explanation: 9×√7× 9×√7 = 81×7 = 567


 

15. Divide 20 by 2√5

(a) √5

(b) 2√5

(c)4√5

(d)3√5

Answer

Answer: (b) 2√5

Explanation: 20/(2√5) =(4×5)/(2√5) = (2×2×√5×√5)/(2√5) = 2√5


 

16. The number obtained by rationalizing the denominator of 1/(6-√5)

(a)(6+√5)/(6-√5)

(b) (6-√5)/31

(c) (6-√5)/(6+√5)

(d)(6+√5)/31

Answer

Answer: (d)(6+√5)/31

Explanation: 1/(6-√5) ×(6+√5)/(6+√5) = (6+√5)/((6)2-(√5)2 )=(6+√5)/(36-5) = (6+√5)/31


 

17.Which of the following is equal to x2

(a)x4-x

(b) x4x

(c) x4x-3

(d) x4x-2

Answer

Answer: (d) x4x-2

Explanation: x4x-2 = x4-2 = x2


 

18. (6√5 + 7√3)(6 √5 – 7√3) is equal to

(a)23

(b)33

(c)43

(d)45

Answer

Answer: (b)33

Explanation: (6√5 + 7√3)(6 √5 – 7√3) = (6√5)2-(7√3)2

= (36×5) – (49×3)

= 180 – 147

= 33


 

19. Which of the following is a rational number?

(a)2

(b) √9

(c)both (a) and (b)

(d)None of these

Answer

Answer: (c)both (a) and (b)

Explanation: √9=3 which is a rational number.


 

20. √2+√9 is a/an

(a)irrational number

(b)rational number

(c) both rational and irrational

(d)None of these

Answer

Answer: (a)irrational number

Explanation: √2+√9 = √2+3

√2 is an irrational number and 3 is a rational number, and sum of a rational and irrational number is always an
irrational number

Hence, √2+√9 is an irrational number.


 

Number System Class 9 MCQ with Answers

21.Which of the following is a rational number

(a)π

(b)√2

(c) √3

(d)1.3478

Answer

Answer: (d)1.3478

Explanation: 1.3478 can be represented in the (p )/q form i.e.,

1.3478=13478/10000


 

22. Value of the expression (√2+7√5)2 is

(a) 247 + 14√10

(b) 24 + 14√10

(c) 247 + √10

(d)None of these

Answer

Answer: (a) 247 + 14√10

Explanation: (√2+7√5)2 = (√2)2 +2(√2)( 7√5)+( 7√5)2

= 2 +14√10 + 245

= 247 + 14√10





23. The value of the expression (√3+√5)/(√3-√5) after rationalising the denominator is

(a) 4-√15

(b) 8+√15

(c) -4-√15

(d)- 4-2√15

Answer

Answer: (c) -4-√15

Explanation: (√3+√5)/(√3-√5)× (√3+√5)/(√3+√5) = (√3+√5)2/((√3)2-(√5)2 )

= ((√3)2+2(√3)(√5)+(√5)2)/(3-5)

= (3+2√15+5)/(-2)

= (8+2√15)/(-2)

= -[4+√15]


 

24. The value obtained after simplifying 72.7(2/3) is

(a) 7(8/3)

(b) 7(2/3)

(c)  72

(d) 7(4/3);

Answer

Answer: (a) 7(8/3)

Explanation: am.an = (a)m+n

Using above identity

72.7(2/3) = 7(2+2/3) = 7(8/3)


 

25. (9(3/2))8 is equal to

(a) 92

(b) 912

(c) 93

(d) All of these

Answer

Answer: (b) 912

Explanation: (9(3/2))8 = 9(3/2×)8 = 912


 

26. The value obtained after simplifying 5(2/9)/5(1/7) is

(a) 5(5/63 )

(b) 5(1/63 )

(c) 5(14/63 )

(d) 5((-5)/63 )

Answer

Answer: (a) 5(5/63 )

Explanation: 5(2/9)/5(1/7) = 5((2/9 – 1/7))

= 5(((14-9)/63)) = 5(5/63 )


 

27.a-p.7-p =

(a)7a

(b) a-p

(c) (7a)-p

(d) 7-p;

Answer

Answer: (c) (7a)-p

Explanation: a-p.7-p = (7a)-p


 

28. (2√3-√7)( (2√3+√7) +(3√3+√2)2 =

(a) 2(17+3√6)

(b) 34+6√6

(c) Both (a) and (b)

(d) None of these

Answer

Answer: (c) Both (a) and (b)

Explanation: (2√3-√7)( (2√3+√7) +(3√3+√2)2

= (2√3)2 – (√7)2 + (3√3)2 + 2((3√3)(√2) + (√2)2

= 12 – 7 +27 + 6√6 +2

= 34+6√6

= 2(17+3√6)


 

29. (2((-3)/2))[ (25+5((-3)/2))] =

(a) (2(7/2)) + (10((-3)/2)))

(b) (2(7/2)) + (10(3/2))

(c) (2(-7/2) + (10-3/2)

(d) (10(7/2) + (2(-3/2))

Answer

Answer: (a) (2(7/2)) + (10((-3)/2)))

Explanation: (2((-3)/2))[ (25+5((-3)/2))] = (2((-3)/2)) (2^5)+ (2((-3)/2)) (5((-3)/2))

= (2((-3)/2+5)) + (10((-3)/2))

= (2((-3+10)/2)) + (10((-3)/2))

= (2(7/2)) + (10((-3)/2)))


 

30. (2-√2)2 – 6 + 4√2

(a)1

(b)2

(c)3

(d)0

Answer

Answer: (d)0

Explanation: (2-√2)2– 6 + 4√2 = (2)2-2(2) (√2) + (√2)2– 6 + 4√2

= 4 -4√2 +2 – 6 + 4√2

= 6 – 4√2- 6 + 4√2

= 0


 

MCQ Questions for Class 9 Maths

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