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.
Answer
Answer: (a)
Question 2.
\(\frac{1}{2}\) is 2
(a) a natural number
(b) a whole number
(c) an integer
(d) a rational number.
Answer
Answer: (d)
Question 3.
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.
Answer
Answer: (a)
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.
Answer
Answer: (b)
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.
Answer
Answer: (c)
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.
Answer
Answer: (d)
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.
Answer
Answer: (c)
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.
Answer
Answer: (b)
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.
Answer
Answer: (a)
Question 10.
The rational number which is equal to its negative is
(a) 0
(b) -1
(c) 1
(d) \(\frac{1}{2}\)
Answer
Answer: (a)
Question 11.
The reciprocal of \(\frac{1}{x}\) (x ? 0) is
(a) x
(b) \(\frac{1}{x}\)
(c) 1
(d) 0
Answer
Answer: (a)
Question 12.
The reciprocal of a positive rational number is
(a) a positive rational number
(b) a negative rational number
(c) 0
(d) 1.
Answer
Answer: (a)
Question 13.
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.
Answer
Answer: (b)
Question 14.
(a + b) + c = a + (b + c) is called
(a) commutative law for multiplication
(b) commutative law for addition
(c) associative law for addition
id) associative law for multiplication.
Answer
Answer: (c)
Question 15.
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.
Answer
Answer: (b)
Question 16.
a(b + c) = ab + ac is called
(a) commutative law
(b) associative law
(c) distributive law
(d) none of these.
Answer
Answer: (c)
Question 17.
The additive identity for rational numbers is
(a) 1
(b) -1
(c) 0
(d) none of these.
Answer
Answer: (c)
Question 18.
The multiplicative identity for rational numbers is
(a) -1
(b) 1
(c) 0
(d) none of these.
Answer
Answer: (b)
Question 19.
The additive inverse of \(\frac{2}{3}\) is
(a) –\(\frac{2}{3}\)
(b) \(\frac{3}{2}\)
(c) –\(\frac{3}{2}\)
(d) 1
Answer
Answer: (a)
(d) 1
Question 20.
The additive inverse of –\(\frac{3}{4}\) is
(a) –\(\frac{3}{4}\)
(b) 1
(c) 0
(d) \(\frac{3}{4}\)
Answer
Answer: (d)
Question 21.
The multiplicative inverse of \(\frac{1}{2}\) is
(a) 1
(b) -1
(c) 2
(d) 0
Answer
Answer: (c)
Question 22.
The multiplicative inverse of –\(\frac{2}{5}\) is
(a) –\(\frac{2}{5}\)
(b) –\(\frac{5}{2}\)
(c) \(\frac{5}{2}\)
(d) 1
Answer
Answer: (b)
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.
Answer
Answer: (d)
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.
Answer
Answer: (a)
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.
Answer
Answer: (a)
Question 26.
The multiplicative inverse of 1 is
(a) 0
(b) -1
(c) 1
(d) none of these.
Answer
Answer: (c)
Question 27.
The multiplicative inverse of -1 is
(a) 0
(b) -1
(c) 1
(d) none of these.
Answer
Answer: (b)
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.
Answer
Answer: (c)
Question 29.
The negative of 2 is
(a) 2
(b) \(\frac{1}{2}\)
(c) -2
(d) –\(\frac{1}{2}\)
Answer
Answer: (c)
Question 30.
The negative of -2 is
(a) -2
(b) 2
(c) –\(\frac{1}{2}\)
(d) \(\frac{1}{2}\)
Answer
Answer: (b)
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
Answer
Answer: (b)
Question 32.
The rational number that does not have a reciprocal is
(a) 0
(b) 1
(c) -1
(d) \(\frac{1}{2}\)
Answer
Answer: (a)
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.
Answer
Answer: (b)
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.
Answer
Answer: (c)
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.
Answer
Answer: (d)
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