Give the additive inverse of - 2 - 5 .

Given, - 2 - 5 . Now, we can write - 2 - 5 = 2 5 . We need to find the additive inverse of 2 5 . We know that if the sum of two rational numbers is 0 , then the two numbers are called additive inverses of each other. This means for every rational number a b , there is a rational number - a b such that a b + - a b is 0 . So, the additive inverse of 2 5 = - 2 5 . Hence, the required additive inverse is - 2 5 .

Give the additive inverse of - 2 - 5 .

Given, - 2 - 5 . Now, we can write - 2 - 5 = 2 5 . We need to find the additive inverse of 2 5 . We know that if the sum of two rational numbers is 0 , then the two numbers are called additive inverses of each other. This means for every rational number a b , there is a rational number - a b such that a b + - a b is 0 . So, the additive inverse of 2 5 = - 2 5 . Hence, the required additive inverse is - 2 5 .

E M B I B E

Foundation Course Mathematics>Chapter -1 - Rational Numbers>EXERCISE>Q 3

EASY

7th CBSE

IMPORTANT

Earn 100

Give the additive inverse of $\frac{- 2}{- 5}$ .

Important Points to Remember in Chapter -1 - Rational Numbers from Subject Experts Foundation Course Mathematics Solutions

1. Rational Number and Its Properties:

(i) Numbers that can be expressed in the form $\frac{p}{q}$ , where $q$ is a non-zero integer and $p$ is any integer are called rational numbers.

(ii) Every integer is a rational number, but a rational number need not be an integer.

(iii) A rational number $\frac{p}{q}$ is said to be in the standard form if $q$ is a positive integer and the integers $p, q$ have no common divisor other than $1$ .

(iv) A rational number $\frac{p}{q}$ is positive, if $p$ and $q$ are either both positive or both negative.

(v) A rational number $\frac{p}{q}$ is negative, if $p$ and $q$ are of opposite signs.

(vi) Two rational numbers are equal if they have the same standard form.

(vii) To convert a rational number to an equivalent rational number, multiply or divide both its numerator and denominator by a non-zero integer.

(viii) If there are two rational numbers with a common denominator, then one with the larger numerator is larger than the other.

(ix) A positive rational number is greater than zero.

(x) Every negative rational number is less than zero.

(xi) Rational numbers can be represented on the number line.

2. Operations on Rational Numbers:

(i) For any two rational numbers $\frac{p}{q}$ and $\frac{r}{q}$ we define:
$\frac{p}{q} + \frac{r}{q} = \frac{p + r}{q}$ .

(ii) For any two rational numbers $\frac{p}{q}$ and $\frac{r}{s}$ , to find $\frac{p}{q} + \frac{r}{s}$ , first we convert $\frac{p}{q}$ and $\frac{r}{s}$ to equivalent rational numbers having denominator equal to the LCM of $q$ and $s$ and then they are added.

(iii) For any two rational numbers $\frac{p}{q}$ and $\frac{r}{s}$ , we have. $\frac{p}{q} - \frac{r}{s} = \frac{p}{q} + (negative of \frac{r}{s})$ .

(iv) For any two rational numbers $\frac{p}{q}$ and $\frac{r}{s}$ , we have, $\frac{p}{q} \times \frac{r}{s} = \frac{p \times r}{q \times s}$ .

(v) The reciprocal of a non-zero rational number $\frac{p}{q}$ is $\frac{q}{p}$ and we write, ${(\frac{p}{q})}^{- 1} = \frac{q}{p}$ .

(vi) For any two rational numbers $\frac{p}{q}$ and $\frac{r}{s} (\neq 0)$ , we have, $\frac{p}{q} \div \frac{r}{s} = \frac{p}{q} \times \frac{s}{r}$ .