Question:
What should be added to $\left(\frac{2}{3}+\frac{3}{5}\right)$ to get $\frac{-2}{15} ?$
Solution:
Let $x$ be added.
$\therefore x+\left(\frac{2}{3}+\frac{3}{5}\right)=\frac{-2}{15}$
$\Rightarrow x+\left(\frac{10}{15}+\frac{9}{15}\right)=\frac{-2}{15}$
$\Rightarrow x+\left(\frac{10+9}{15}\right)=\frac{-2}{15}$
$\Rightarrow x=\frac{-2}{15}-\frac{19}{15}$
$\Rightarrow x=\frac{-2-19}{15}$
$\Rightarrow x=\frac{-21}{15}$
$\Rightarrow x=\frac{-7}{5}$