2) 1 1 1 - 14 63

2) $$\frac{1}{\frac{1}{14} - \frac{1}{63}} = \frac{1}{\frac{1 \cdot 9}{14 \cdot 9} - \frac{1 \cdot 2}{63 \cdot 2}} = \frac{1}{\frac{9}{126} - \frac{2}{126}} = \frac{1}{\frac{7}{126}} = \frac{126}{7} = 18$$

Ответ: 18