Test: Rational Numbers - Class 7 MCQ

Additive identity means that to any number if this identity is added, the number remains the same. So additive identity is 0 which means 0 added to any no. does not affect it.

1 is the multiplicative identity which means that identity of the number remains intact if it is multiplied by 1

Let we have a rational number having numerator as 2 and denominator as 3. The rational form is given by :

2/3

Reciprocal of a number is such that the numerator becomes denominator and the denominator becomes numerator. So, the reciprocal of the above rational no will be :

3/2

The reciprocal of the reciprocal of a rational number will be again  2/3. Hence, the reciprocal of the reciprocal of a rational number is the number itself.

• Let the numbers be x and y
• xy = -20/9 as given by the question
• now one number is given 4 , let x = 4
• Now we just have to find y
• 4.y = -20/9
• On solving we get , y = -5/9
   

Reciprocal of 1 and -1 are their own reciprocals.

1 = 1/1 and its reciprocal is 1/1 i.e. 1. ( Number itself)

-1= -1/1

Its reciprocal= 1/-1= -1 (number itself)

- The reciprocal of a number is 1 divided by that number.
- For –5, the reciprocal is calculated as:
1/-5 = -1/5
- Therefore, the reciprocal of –5 is –1/5.

Reciprocal is the inverse of the number, meaning, the numerator becomes denominator and denominator becomes numerator.so 1/x become x/1

he product of two rational numbers is always a rational number.