Найдите значение выражения: а) \(\frac{7}{15} + \frac{3}{10}\); б) \(\frac{7}{15} - \frac{3}{10}\); в) \(\frac{5}{12} \cdot \frac{9}{20}\); г) \(\frac{5}{12} : \frac{9}{20}\); д) \((\frac{5}{7} + 3\frac{14}{18}) + \frac{2}{7}\); e) \(16\frac{19}{40} - (13 + 1\frac{19}{40})\).

Давай найдем значения выражений: а) \(\frac{7}{15} + \frac{3}{10}\) = \(\frac{7 \(\cdot\) 2}{15 \(\cdot\) 2} + \frac{3 \(\cdot\) 3}{10 \(\cdot\) 3}\) = \(\frac{14}{30} + \frac{9}{30}\) = \(\frac{23}{30}\) б) \(\frac{7}{15} - \frac{3}{10}\) = \(\frac{7 \(\cdot\) 2}{15 \(\cdot\) 2} - \frac{3 \(\cdot\) 3}{10 \(\cdot\) 3}\) = \(\frac{14}{30} - \frac{9}{30}\) = \(\frac{5}{30}\) = \(\frac{1}{6}\) в) \(\frac{5}{12} \cdot \frac{9}{20}\) = \(\frac{5 \(\cdot\) 9}{12 \(\cdot\) 20}\) = \(\frac{45}{240}\) = \(\frac{3}{16}\) г) \(\frac{5}{12} : \frac{9}{20}\) = \(\frac{5}{12} \cdot \frac{20}{9}\) = \(\frac{5 \(\cdot\) 20}{12 \(\cdot\) 9}\) = \(\frac{100}{108}\) = \(\frac{25}{27}\) д) \((\frac{5}{7} + 3\frac{14}{18}) + \frac{2}{7}\) = \((\frac{5}{7} + \frac{27 \(\cdot\) 3 + 14}{9}) + \frac{2}{7}\) = \((\frac{5}{7} + \frac{95}{9}) + \frac{2}{7}\) = \((\frac{5 \(\cdot\) 9 + 95 \(\cdot\) 7}{63}) + \frac{2 \(\cdot\) 9}{7 \(\cdot\) 9}\) = \((\frac{45 + 665}{63}) + \frac{18}{63}\) = \(\frac{710}{63} + \frac{18}{63}\) = \(\frac{728}{63}\) = 11\(\frac{35}{63}\) = 11\(\frac{5}{9}\) е) \(16\frac{19}{40} - (13 + 1\frac{19}{40})\) = \(16\frac{19}{40} - 13 - 1\frac{19}{40}\) = \(16 - 13 - 1 + \frac{19}{40} - \frac{19}{40}\) = 2

Ответ: a) \(\frac{23}{30}\); б) \(\frac{1}{6}\); в) \(\frac{3}{16}\); г) \(\frac{25}{27}\); д) 11\(\frac{5}{9}\); e) 2

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