Test: Rational Numbers- 1


10 Questions MCQ Test NCERT Mathematics for CAT Preparation | Test: Rational Numbers- 1


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Attempt Test: Rational Numbers- 1 | 10 questions in 10 minutes | Mock test for Class 8 preparation | Free important questions MCQ to study NCERT Mathematics for CAT Preparation for Class 8 Exam | Download free PDF with solutions
QUESTION: 1

Find the reciprocal of -2.

Solution:

reciprocal means interchanging numerator and denominator here it's-2/1 understand after reciprocal denominator came upside so, it will be -1/2 

QUESTION: 2

Which of the following is the reciprocal of the reciprocal of a rational number?

Solution:

The reciprocal of the reciprocal of a rational number is the number itself.
For example, Consider the rational no. 1/2. It's reciprocal is 2 and the reciprocal of 2 is 1/2. Therefore, it's the number itself.

QUESTION: 3

What is the additive inverse of -2/3?

Solution:

Additive inverse of a number is the number who when added to initial number sums up to zero.

If x is a negative number, then its additive inverse is equal and opposite in sign to it. This means that the additive inverse of a negative number is positive.

Hence, additive inverse of -2/3 is 2/3

So option C is the correct answer. 

QUESTION: 4

Find the multiplicative inverse of -13.

Solution:

In order to  find the multiplicative inverse of  the given number, find the reciprocal of that number.
Here the given number is -13
So the reciprocal of -13 will be -1/13

Therefore, option C is the correct answer. 

 

QUESTION: 5

Which of the following is the reciprocal of a rational number?

Solution:

Clearly, we can see that -1 and 1 are the numbers whose reciprocal is the number itself.
1 and -1 are the only rational numbers which are their own reciprocals. No other rational number is its own reciprocal. We know that there is no rational number which when multiplied with 0, gives 1. Therefore, rational number 0 has no reciprocal or multiplicative inverse.

QUESTION: 6

Which of the following statements is true?

Solution:

Every rational number is not a fraction.
In rational numbers, we use integers and in fractions, we use only natural numbers.

QUESTION: 7

For any three rational numbers a, b and c, a + (b + c) = __________.

Solution:

It is the associative property and we know that the rational numbers are associative under addition.
 For eg: 5/3 + (3/2 + 1/3) = 7/2;
  (5/3 + 3/2) + 1/3 = 7/2
Here, Option 'a' is the correct answer.

Therefore, a+(b+c) = (a+b)+c

QUESTION: 8

Which of the following is the Multiplicative identity for rational numbers?

Solution:

1 is the multiplicative identity for rational numbers, natural numbers, integers.

QUESTION: 9

Which of the following is the product of (-7/8) and 4/21?

Solution:

-7 / 8 x 4 / 21 = - 1 / 6 

So option A is the correct answer. 

QUESTION: 10

Which of the following is the identity element under addition?

Solution:

Zero is called the identity for the addition of rational numbers.
Example: 2/3 + 0 = 2/3

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