80. Найдите значение выражения: 1) \(4\frac{1}{5} \cdot \frac{7}{15} \cdot \frac{1}{3};\) 3) \((5\frac{8}{9} \cdot 1\frac{17}{36} + 1\frac{1}{4}) \cdot 4\frac{1}{5}\)

1) \(4\frac{1}{5} \cdot \frac{7}{15} \cdot \frac{1}{3} = \frac{21}{5} \cdot \frac{7}{15} \cdot \frac{1}{3} = \frac{21 \cdot 7 \cdot 1}{5 \cdot 15 \cdot 3} = \frac{7 \cdot 7 \cdot 1}{5 \cdot 5 \cdot 3} = \frac{49}{75}\)

Ответ: \(\frac{49}{75}\)

3) \((5\frac{8}{9} \cdot 1\frac{17}{36} + 1\frac{1}{4}) \cdot 4\frac{1}{5} = (\frac{53}{9} \cdot \frac{53}{36} + \frac{5}{4}) \cdot \frac{21}{5} = (\frac{2809}{324} + \frac{5}{4}) \cdot \frac{21}{5} = (\frac{2809}{324} + \frac{5 \cdot 81}{4 \cdot 81}) \cdot \frac{21}{5} = (\frac{2809}{324} + \frac{405}{324}) \cdot \frac{21}{5} = \frac{3214}{324} \cdot \frac{21}{5} = \frac{1607}{162} \cdot \frac{21}{5} = \frac{1607 \cdot 21}{162 \cdot 5} = \frac{33747}{810} = \frac{11249}{270} = 41\frac{179}{270}\)

Ответ: \(41\frac{179}{270}\)