Fill in the blanks:
(i) The product of two positive rational numbers is always______.
(ii) The product of a positive rational number and a negative rational number is always________.
(iii) The product of two negative rational numbers is always________.
(iv) The reciprocal of a positive rational number is________.
(v) The reciprocal of a negative rational number is________.
(vi) Zero has reciprocal. The product of a rational number and its reciprocal is______.
(viii) The numbers and are their own reciprocals______.
(ix) If a is reciprocal of b, then the reciprocal of b is______.
(x) The number 0 is the reciprocal of any number______.
(xi) Reciprocal of $\frac{1}{a}$, $a≠0$ is______.
(xii) $(17 \times 12)^{-1} = 17^{-1} \times$________ .


To do:

We have to fill in the given blanks.

Solution:

(i) The product of two positive rational numbers is always positive.

For example,

$5\times4=20$

(ii) The product of a positive rational number and a negative rational number is always negative.

For example,

$5\times(-4)=-20$

(iii) The product of two negative rational numbers is always positive.

For example,

$(-5)\times(-4)=20$ 

(iv) The reciprocal of a positive rational number is positive.

For example,

Reciprocal of 5 is $\frac{1}{5}$ . 

(v) The reciprocal of a negative rational number is negative.

For example,

Reciprocal of $-5$ is $\frac{-1}{5}$ .  

(vi) Any number divided by zero is not defined.

Therefore,

Zero has no reciprocal. 

(vii) The product of a rational number and its reciprocal is 1.

For example,

Reciprocal of 5 is $\frac{1}{5}$

$5\times\frac{1}{5}=1$

(viii) The numbers that are their own reciprocals are $1$ and $-1$.

For example,

Reciprocal of 1 is $\frac{1}{1}=1$

Reciprocal of $-1$ is $\frac{1}{-1}=\frac{-1}{1}=-1$

(ix) If $a$ is reciprocal of $b$, then the reciprocal of $b$ is $a$.

For example,

Reciprocal of 5 is $\frac{1}{5}$

Reciprocal of $\frac{1}{5}=\frac{1}{\frac{1}{5}}$

$=\frac{5}{1}$

$=5$

(x) Any number divided by zero is not defined.

Therefore,

The number 0 is not the reciprocal of any number.

(xi) Reciprocal of $a$ where $a≠0$ is $\frac{1}{a}$.

Therefore,

Reciprocal of $\frac{1}{a}$, $a≠0$ is $a$.

(xii) $(a \times b)^{-1}=(a)^{-1}\times(b)^{-1}$ where $a, b≠0$.

This implies,

$(17 \times 12)^{-1} = 17^{-1} \times12^{-1}$

Updated on: 10-Oct-2022

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