Вариант 4 1. Выполните действие: a) 5.7; B) 5.2 :, 4 16 9 б) 6) г) 124; e): 6. 2716' 18 19

а) $$\frac{5}{9} \cdot \frac{7}{8} = \frac{5 \cdot 7}{9 \cdot 8} = \frac{35}{72}$$

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) $$\frac{5}{6} \cdot 2\frac{4}{7} = \frac{5}{6} \cdot \frac{2 \cdot 7 + 4}{7} = \frac{5}{6} \cdot \frac{18}{7} = \frac{5 \cdot 18}{6 \cdot 7} = \frac{5 \cdot 3}{1 \cdot 7} = \frac{15}{7} = 2\frac{1}{7}$$

г) $$1\frac{5}{12} \cdot 24 = \frac{1 \cdot 12 + 5}{12} \cdot 24 = \frac{17}{12} \cdot 24 = \frac{17 \cdot 24}{12} = 17 \cdot 2 = 34$$

д) $$\frac{4}{9} : \frac{16}{45} = \frac{4}{9} \cdot \frac{45}{16} = \frac{4 \cdot 45}{9 \cdot 16} = \frac{1 \cdot 5}{1 \cdot 4} = \frac{5}{4} = 1\frac{1}{4}$$

e) $$\frac{18}{19} : 6 = \frac{18}{19} \cdot \frac{1}{6} = \frac{18 \cdot 1}{19 \cdot 6} = \frac{3 \cdot 1}{19 \cdot 1} = \frac{3}{19}$$

Ответ: а) $$\frac{35}{72}$$, б) $$\frac{1}{12}$$, в) $$2\frac{1}{7}$$, г) $$34$$, д) $$1\frac{1}{4}$$, е) $$\frac{3}{19}$$