2 5 2 (10)+(-)

\(
\begin{aligned}
&10) \frac{2}{15} + \left(\frac{5}{7} - \frac{2}{9}\right) = \frac{2}{15} + \left(\frac{5 \cdot 9}{7 \cdot 9} - \frac{2 \cdot 7}{9 \cdot 7}\right) = \frac{2}{15} + \left(\frac{45}{63} - \frac{14}{63}\right) = \frac{2}{15} + \frac{31}{63} = \frac{2 \cdot 21}{15 \cdot 21} + \frac{31 \cdot 5}{63 \cdot 5} = \frac{42}{315} + \frac{155}{315} = \frac{197}{315}
\end{aligned}
\)