Rational Numbers For Class 8 Maths MCQ Questions -

Q 1. Which of the following statements is false?
(a) Natural numbers are closed under addition
(b) Whole numbers are closed under addition
(c) Integers are closed under addition
(d) Rational numbers are not closed under addition.

Ans. (d) Rational numbers are not closed under addition.

Q 2. Which of the following statements is false?
(a) Natural numbers are closed under subtraction
(b) Whole numbers are not closed under subtraction
(c) Integers are closed under subtraction
(d) Rational numbers are closed under subtraction.

Ans. (a) Natural numbers are closed under subtraction

Q 3. The additive identity for rational numbers is
(a) 1
(b) –1
(c) 0
(d) None of these

Ans. (c) 0

Q 4. Which of the following statements is true?
(a) Natural numbers are closed under multiplication
(b) Whole numbers are not closed under multiplication
(c) Integers are not closed under multiplication
(d) Rational numbers are not closed under multiplication.

Ans. (a) Natural numbers are closed under multiplication

Q 5. The additive inverse of $\frac {7}{11}$ is

$(a) \frac {7}{11}\$

$(b) \frac {11}{7}\\$

$(c) \frac {-11}{7}$

(d) 1

Ans. $(c) \frac {-11}{7}$

Q 6. Which of the following statements is true ?
(a) Natural numbers are closed under division
(b) Whole numbers are not closed under division
(c) Integers are closed under division
(d) Rational numbers are closed under division.

Ans. (b) Whole numbers are not closed under division

Q 7. What should be added to $\frac{-3}{4}$ to get –1?

(a) $\frac{1}{4}$

$(b)\frac{-1}{4}\\$

$(d)\frac{-3}{4}\\$

$Ans.(b)\frac{-1}{4}\\$

Q 8. Which of the following statements is false ?
(a) Natural numbers are commutative for addition
(b) Whole numbers are commutative for addition
(c) Integers are not commutative for addition
(d) Rational numbers are commutative for addition.

Ans. (c) Integers are not commutative for addition

Q 9. Which of the following statements is true ?
(a) Natural numbers are commutative for subtraction
(b) Whole numbers are commutative for subtraction
(c) Integers are commutative for subtraction
(d) Rational numbers are not commutative for subtraction.

Ans. (d) Rational numbers are not commutative for subtraction

Q 10. Fill in the blanks:

The multiplicative inverse of a number is also called its Reciprocal.
The negative of a rational number is called its additive inverse.
The product of $\frac{-27}{81}$ and $\frac{81}{-27}$ is 1
The rational number equivalent to 3 is $\frac{6}{2}$

Q 11. Which of the following statements is true ?
(a) Natural numbers are associative for addition
(b) Whole numbers are not associative for addition
(c) Integers are not associative for addition
(d ) Rational numbers are not associative for addition.

Ans. (a) Natural numbers are associative for addition

Q 12. Which of the following is the product of $\frac{-7}{8} and \frac{4}{21}?$

$(a)\frac{-1}{6}$

(b) 12

$(c)\frac{-63}{16}$

$(d) \frac{-16}{147}$

$Ans. (a) \frac{-1}{6}$

Q 13. Which of the following statements is true ?
(a) Natural numbers are associative for subtraction
(b) Whole numbers are not associative for subtraction
(c) Integers are associative for subtraction
(d) Rational numbers are associative for subtraction.

Ans. (b) Whole numbers are not associative for subtraction

Q 14. 0 is not
(a) a natural number
(b) a whole number
(c) an integer
(d) a rational number.

Ans. (a) a natural number

Q 15. Which of the following is a rational number between $\frac{1}{4}and\frac{1}{3}$ ?

$(a) \frac{7}{24}$

$(b) \frac{8}{15}$

$(c) \frac{13}{48}$

(d) Both (a) and (c)

Ans. (d) Both (a) and (c)

Q 16. $\frac{1}{2}$ is 2
(a) a natural number
(b) a whole number
(c) an integer
(d) a rational number.

Ans. (d) a rational number.

Q 17. a + b = b + a is called
(a) commutative law of addition
(b) associative law of addition
(c) distributive law of addition
(d) none of these.

Ans. (a) commutative law of addition

Q 18. By what rational number should $\frac{-3}{5}$ be multiplied to obtain 21?

$(a) \frac{507}{4}$

(b) 35

(d) 507

Ans. (c) –35

Q 19. a × b = b × a is called
(a) commutative law for addition
(b) commutative law for multiplication
(c) associative law for addition
id) associative law for multiplication.

Ans. (b) commutative law for multiplication

Q 20. (a + b) + c = a + (b + c) is called
(a) commutative law for multiplication
(b) commutative law for addition
(c) associative law for addition
(d) associative law for multiplication.

Ans. (c) associative law for addition

Q 21. A number which can be written in the form, p/q where p and q are integers and _____ is called a rational number.

(a) q = 0

(b) q ≠ 0

(d) None of these

Ans. (b) q ≠ 0

Q 22. a × (b × c) = (a × b) × c is called
(a) associative law for addition
(b) associative law for multiplication
(c) commutative law for addition
(d) commutative law for multiplication.

Ans. (b) associative law for multiplication

Q 23. a (b + c) = ab + ac is called
(a) commutative law
(b) associative law
(c) distributive law
(d) none of these.

Ans. (c) distributive law

Q 24. Which of the following is the reciprocal of the reciprocal of a rational number?

(a) -1

(b) 0

(d) None of these

Ans. (c) The number itself

Q 25. The additive identity for rational numbers is
(a) 1
(b) –1
(c) 0
(d) none of these.

Ans. (c) 0

Q 26. The multiplicative identity for rational numbers is
(a) –1
(b) 1
(c) 0
(d) none of these.

Ans. (b) 1

Q 27. The additive inverse of $\frac{2}{3}$ is
$(a) \frac{-2}{3}$
$(b) \frac{3}{2}$
$(c) \frac{-3}{2}$
(d) 1

$Ans. (a) \frac{-2}{3}$

Q 28. The multiplicative inverse of $\frac{1}{2}$ is
(a) 1
(b) –1
(c) 2
(d) 0

Ans. (c) 2

Q 29. The multiplicative inverse of 1 is
(a) 0
(b) –1
(c) 1
(d) none of these.

Ans. (c) 1

Q 30. The multiplicative inverse of -1 is
(a) 0
(b) –1
(c) 1
(d) none of these.

Ans. (b) -1

Q 31. How many rational numbers are there between any two given rational numbers?
(a) Only one
(b) Only two
(c) Countless
(d) Nothing can be said.

Ans. (c) Countless

Q 32. The rational number that does not have a reciprocal is
(a) 0
(b) 1
(c) –1
$(d) \frac{1}{2}$

Ans. (a) 0

Q 33. The reciprocal of $\frac{1}{x}$ (x ≠ 0) is
(a) x
$(b) \frac{1}{x}$
(c) 1
(d) 0

Ans. (a) x

Q 34. The reciprocal of a positive rational number is
(a) a positive rational number
(b) a negative rational number
(c) 0
(d) 1

Ans. (a) a positive rational number

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