Вычислите: e) $$\frac{9}{14} + \frac{5}{21}$$

$$\frac{9}{14} + \frac{5}{21} = \frac{9 \cdot 3}{14 \cdot 3} + \frac{5 \cdot 2}{21 \cdot 2} = \frac{27}{42} + \frac{10}{42} = \frac{27 + 10}{42} = \frac{37}{42}$$ Ответ: $$\frac{37}{42}$$