1. Выполните действие: a) 5/9 * 7/8; в) 5/6 * 2 4/7; д) 4/9 : 16/45; б) 4/27 * 9/16; г) 1 5/12 * 24; e) 18/19 : 6.

a)

\[\frac{5}{9} \cdot \frac{7}{8} = \frac{5 \cdot 7}{9 \cdot 8} = \frac{35}{72}\]

б)

\[\frac{4}{27} \cdot \frac{9}{16} = \frac{4 \cdot 9}{27 \cdot 16} = \frac{1 \cdot 1}{3 \cdot 4} = \frac{1}{12}\]

в)

\[5 \frac{5}{6} \cdot 2 \frac{4}{7} = \frac{35}{6} \cdot \frac{18}{7} = \frac{35 \cdot 18}{6 \cdot 7} = \frac{5 \cdot 3}{1 \cdot 1} = \frac{15}{1} = 15 \]

г)

\[1 \frac{5}{12} \cdot 24 = \frac{17}{12} \cdot 24 = \frac{17 \cdot 24}{12} = 17 \cdot 2 = 34\]

д)

\[\frac{4}{9} : \frac{16}{45} = \frac{4}{9} \cdot \frac{45}{16} = \frac{4 \cdot 45}{9 \cdot 16} = \frac{1 \cdot 5}{1 \cdot 4} = \frac{5}{4}\]

е)

\[\frac{18}{19} : 6 = \frac{18}{19} \cdot \frac{1}{6} = \frac{18 \cdot 1}{19 \cdot 6} = \frac{3 \cdot 1}{19 \cdot 1} = \frac{3}{19}\]