CBSE class8 Rational numbers

A number of the form p/q is said to be a rational number if

• p and q are integers

• p and q are integers and p is not equal to zero.

• p and q are integers and q is not equal to zero.

• and q are integers and p and q both are not equal to zero.

-(-x) is same as

• -x

• x

• 1/x

• -1/x

Addition is associative for

• Natural numbers

• Whole numbers

• Rational numbers

• All of these

Reciprocal of x is

• -x

• 1/x

• x+1

• x

Additive identity of rational numbers is

• 1

• -1

• x

• 0

Rational numbers are not closed under

• Subtraction

• Division

• Addition

• Multiplication

The additive inverse of a/b is

• -b/a

• b/a

• a/b

• -a/b

Which of the following is not a rational number?

-2/3 , 1/8 , 0 ,18 , 54

• 18 and 54

• -2/3 and 1/8

• 0

• All are rational numbers

Rational numbers are commutative for

• Subtraction

• Division

• Addition and Subtraction

• Addition and Multiplication

Which of these is a positive rational number?

• $-\frac{5}{6}$

• $\frac{5}{-6\ }$

• $\frac{0}{6}$

• $\frac{-5}{-6\ }$