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# Rational numbers - CSEET QT MCQ

1. If 3 4 = ? 12 then ? =

(a) 3

(b) 6

(c) 9 (

d) 12

2. If 4 5 = 12 ? then ? =

(a) 5

(b) 10

(c) 15

(d) 20

3. If − 8 − 9 = − 16 ? then ? =

(a) 18

(b) -18

(c) 9

(d) -9

4. The rational number −21/28 in standard form is

(a) −3/4

(b) 3/4

(c) 3/7

(d) −3/7

5. The rational number −6/−25 in standard form is

(a) 6/25

(b) −6/25

(c) 6/-25

(d) −6/20

6. Which of the following rational numbers is not equivalent to 7/−4?

(a) 14/−8

(b) 21/−12

(c) 28/−16

(d) 7/−8

7. The sum 5/4 + (- 25/4) =

(a) -5

(b) 5

(c) 4

(d) -4

8. 17/11 – 6/11 =

(a) 1

(b) -1

(c) 6

(d) 3

9. 0 is not

(a) a natural number

(b) a whole number

(c) an integer

(d) a rational number

10. The given property a+b = b+a is known as:

(a) Commutative property

(b) Distributive Property

(c) Associative Property

(d) Closure property

11. If a,b and c are whole numbers, then a+(b+c) = (a+b)+c. This property is called

(a) associative property

(b) distributive Property

(c) commutative property

(d) Closure property

12. The additive identity of any rational number is _____.

(a) 0

(b) 1

(c) -1 (

d) 2

13. 1 is the multiplicative identity for ........

(a) whole numbers

(b) integers

(c) rational numbers

(d) all of the above

14. The additive inverse of 23 is

(a) -23

(b) 32

(c) -32

(d) all of the above

15. The rational number that does not have a reciprocal is

(a) 0

(b) 1

(c) 4

(d) -4

16. An integer can be:

(a) Only Positive

(b) Only Negative

(c) Both positive and negative

(d) None of the above

17. What is the sum of 2/3and 4/9?

(a) 6/3

(b) 6/9

(c) 10/9

(d) 10/3

18. What should be subtracted from -2/3 to get -1?

(a) 1/3

(b) -1/3

(c) 2/3

(d) 2/3

19. What number should be subtracted from both the terms of the ratio 15:19 in order to make it 3:4?

(a) 4

(b) 3

(c) 2

(d) 6

20. Find the multiplicative inverse of 13.

(a) 13

(b) -13

(c) -1/13

(d) 1/13

21. What is the product of 3/10 and 5/6?

(a) 1/6

(b) 1/3

(c) 2/9

(d) 1/4

22. The numbers used for counting objects are called :

(a) Natural numbers

(b) Whole numbers

(c) Integers

(d) None of these

23. The product of two rational numbers is always a _____.

(a) integer

(b) rational number

(c) natural number

(d) whole number

24. Find the sum 6/4 + (-11/4)?

(a) 4/5

(b) -5/4

(c) 6/3

(d) -2/3

25. Find 9/4 × (-8/3) =?

(a) -6/1

(b) -6/5

(c) 4/5

(d) 5/2

1. Answer: (c) 9 Explanation: 3 4 = 3 × 3 4 × 3 = 9/12

2. Answer: (c) 15 Explanation: 4 5 = 4 × 3 5 × 3 = 12/15

3. Answer: (b) -18 Explanation: − 8 − 9 = − 8 × 2 − 9 × 2 = -16/-18

4. Answer: (a) −3/4 Explanation: − 21 28 = − 21 ÷ 7 28 ÷ 7 = -3/4

5. Answer: (a) 6/25 Explanation: − 6 − 25 = − 6 × − 1 − 25 × − 1 = 6/25

6. Answer: (d) 7/-8 Explanation: 7 − 4 = 7 × 2 − 4 × 2 14 − 8 ≠ 7 − 8

7. Answer: (a) -5 Explanation: 5 4 + ( − 25 4 ) = 5 + ( − 25 ) 4 = − 20 4 = -5

8. Answer: (a) 1 Explanation: 17 11 − 6 11 = 17 − 6 11 = 11 11 = 1.

9. Answer: (b) a whole number Explanation: 0 is not a natural number. It is a whole number. Natural numbers only include positive integers.

10. Answer: (a) Commutative property Explanation: Commutative property says that the numbers can be added in any order, and you will still get the same answer. a+b = b+a is a clear example of the commutative property.

11. Answer: (a) associative property Explanation: a+(b+c) = (a+b)+c is associative property of whole numbers.

12. Answer: (a) 0 Explanation: The additive identity property says that if you add a real number to zero or add zero to a real number, then you get the same real number back. The number zero is known as the identity element. Then zero(0) is the additive identity of a real number and all rational numbers are real. Hence, 0 is the additive identity of rational numbers.

13. Answer: (d) all of the above Explanation: We know that whole numbers are a subset of integers which in turn are a subset of rational numbers. Also, 1 is the multiplicative identity for rational numbers because the product of 1 and any rational number is the rational number itself. Thus, 1 is the multiplicative identity for whole numbers, integers, and rational numbers.

14. Answer: (a) -23 Explanation: Additive inverse of 23 will be -23.

15. Answer: (a) 0 Explanation:The rational number that does not have a reciprocal 0 because the reciprocal of 0 is undefined.

16. Answer: (c) Both positive and negative Explanation: An integer can be both positive and negative as well as zero. i.e. …-3, -2, -1, 0, 1, 2, 3,

16. Answer: (c) 10/9 Explanation: 2/3+ 4/9 ⇒ 2/3 x (3/3) + 4/9 ⇒ 6/9 + 4/9 ⇒ 10/9

17. Answer: (a) 1/3 Explanation: Let x be subtracted from -2/3. -2/3 – x = -1 -x = -1 + 2/3 -x = -1/3 x = 1/3

18. Answer: (b) 3 Explanation: Let the required number be x. 15 − x 19 − x = 3 4 60−4x = 57−3x x = 3

19. Answer: (d) 1/13 Explanation: The multiplicative inverse of 13 is (13)1 = 1/13

20. Answer: (d) 1/4 Explanation: The product of 3 /10 and 5/6: ⇒ 3/10 x 5/6 ⇒ (3 x 5)/(10 x 6) ⇒ 15/60 ⇒ 1/4

21. Answer: (a) Natural numbers Explanation: Counting objects are always positive and more than zero.

22. Answer: (b) rational number Explanation: The product of two rational numbers is always a rational number. Let a and b are two rational numbers then a×b will be a rational number.

23. Answer: (b) -5/4 Explanation: 6+4 (-11/4) = 6/4 + (-11) = 6-11/4 = -5/4

25. Answer: (a) -6/1 Explanation: 9/4 × (-8)/3 = 9 × − 8 4 × 3 = -72/12 = 12 × ( − 6 ) 12 × 1 = -6/1