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## Wednesday, 24 February 2021

### CBSE Class 8 Maths - MCQ and Online Tests - Unit 1 - Rational Numbers

#### CBSE Class 8 Maths – MCQ and Online Tests –  Unit 1 – Rational Numbers

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#### CBSE Class 8 Maths – MCQ and Online Tests – Unit 1 – Rational Numbers

Question 1.
0 is not
(a) a natural number
(b) a whole number
(c) an integer
(d) a rational number.

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

Question 3.
a + b = b + a is called
(d) none of these.

Question 4.
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.

Question 5.
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.

Question 6.
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.

Question 7.
Which of the following statements is false ?
(a) Natural numbers are commutative for multiplication
(b) Whole numbers are commutative for multiplication
(c) Integers are not commutative for multiplication
(d) Rational numbers are commutative for multiplication.

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

Question 9.
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.

Question 10.
The rational number which is equal to its negative is
(a) 0
(b) -1
(c) 1
(d) $$\frac{1}{2}$$

Question 11.
The reciprocal of $$\frac{1}{x}$$ (x ? 0) is
(a) x
(b) $$\frac{1}{x}$$
(c) 1
(d) 0

Question 12.
The reciprocal of a positive rational number is
(a) a positive rational number
(b) a negative rational number
(c) 0
(d) 1.

Question 13.
a × b = b × a is called
(b) commutative law for multiplication
id) associative law for multiplication.

Question 14.
(a + b) + c = a + (b + c) is called
(a) commutative law for multiplication
id) associative law for multiplication.

Question 15.
a × (b × c) = (a × b) × c is called
(b) associative law for multiplication
(d) commutative law for multiplication.

Question 16.
a(b + c) = ab + ac is called
(a) commutative law
(b) associative law
(c) distributive law
(d) none of these.

Question 17.
The additive identity for rational numbers is
(a) 1
(b) -1
(c) 0
(d) none of these.

Question 18.
The multiplicative identity for rational numbers is
(a) -1
(b) 1
(c) 0
(d) none of these.

Question 19.
The additive inverse of $$\frac{2}{3}$$ is
(a) –$$\frac{2}{3}$$
(b) $$\frac{3}{2}$$
(c) –$$\frac{3}{2}$$
(d) 1

(d) 1
Question 20.
The additive inverse of –$$\frac{3}{4}$$ is
(a) –$$\frac{3}{4}$$
(b) 1
(c) 0
(d) $$\frac{3}{4}$$

Question 21.
The multiplicative inverse of $$\frac{1}{2}$$ is
(a) 1
(b) -1
(c) 2
(d) 0

Question 22.
The multiplicative inverse of –$$\frac{2}{5}$$ is
(a) –$$\frac{2}{5}$$
(b) –$$\frac{5}{2}$$
(c) $$\frac{5}{2}$$
(d) 1

Question 23.
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.

Question 24.
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.

Question 25.
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.

Question 26.
The multiplicative inverse of 1 is
(a) 0
(b) -1
(c) 1
(d) none of these.

Question 27.
The multiplicative inverse of -1 is
(a) 0
(b) -1
(c) 1
(d) none of these.

Question 28.
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.

Question 29.
The negative of 2 is
(a) 2
(b) $$\frac{1}{2}$$
(c) -2
(d) –$$\frac{1}{2}$$

Question 30.
The negative of -2 is
(a) -2
(b) 2
(c) –$$\frac{1}{2}$$
(d) $$\frac{1}{2}$$

Question 31.
If a and b are two rational numbers, then
(a) $$\frac{a+b}{2}$$ < a
(b) $$\frac{a+b}{2}$$ < b
(c) $$\frac{a+b}{2}$$ = a
(d) $$\frac{a+b}{2}$$ > b

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

Question 33.
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.

Question 34.
Which of the following statements is true ?
(a) Natural numbers are not associative for multiplication
(b) Whole numbers are not associative for multiplication
(c) Integers are associative for multiplication
(d) Rational numbers are not associative for multiplication.

Question 35.
Which of the following statements is true ?
(a) Natural numbers are associative for division
(b) Whole numbers are associative for division
(c) Integers are associative for division
(d) Rational numbers are not associative for division.