Question

What number should be added to $\frac{-5}{7}$ to get $\frac{-2}{3}?$

Answer 1

$$\begin{gathered} \mathrm{Let}x\mathrm{be}\mathrm{added}. \\ \therefore x+\frac{-5}{7}=\frac{-2}{3} \\ \Rightarrow x=\frac{-2}{3}-\frac{-5}{7} \\ \Rightarrow x=\frac{-14}{21}-\frac{-15}{21} \\ \Rightarrow x=\frac{-14-(-15)}{21} \\ \Rightarrow x=\frac{-14+15}{21} \\ \Rightarrow x=\frac{1}{21} \end{gathered}$$