Question

Add the following rational numbers:
$\frac{-2}{5}$ and $\frac{3}{4}$

Answer 1

To, add rational numbers their denominators should be same, so it will become common and numerators will be added to get answer.

$LCM$ of $5$ and $4$ is $20$

$\therefore \frac{-2}{5}=\frac{(-2\times (4\left)\right)}{(5\times (4\left)\right)}=\frac{-8}{20}$

and $\frac{3}{4}=\frac{(3\times (5\left)\right)}{(4\times (5\left)\right)}=\frac{15}{20}$

Now, their denominator is same.

So,

$\frac{-8}{20}+\frac{15}{20}=\frac{-8+15}{20}=\frac{7}{20}$