a) \(\frac{2}{3} \cdot \frac{2}{7} = \frac{2 \cdot 2}{3 \cdot 7} = \frac{4}{21}\)
б) \(\frac{3}{14} \cdot \frac{7}{9} = \frac{3 \cdot 7}{14 \cdot 9} = \frac{21}{126} = \frac{1}{6}\)
в) \(\frac{4}{9} \cdot 27 = \frac{4 \cdot 27}{9} = \frac{108}{9} = 12\)