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

5. Вычисление значений выражений:

1. \( \frac{7}{15} + \frac{3}{10} = \frac{7 \cdot 2}{15 \cdot 2} + \frac{3 \cdot 3}{10 \cdot 3} = \frac{14}{30} + \frac{9}{30} = \frac{14 + 9}{30} = \frac{23}{30} \)
2. \( \frac{7}{12} \cdot \frac{9}{20} = \frac{7 \cdot 9}{12 \cdot 20} = \frac{7 \cdot 3 \cdot 3}{4 \cdot 3 \cdot 20} = \frac{21}{80} \)
3. \( \frac{5}{15} - \frac{3}{10} = \frac{1}{3} - \frac{3}{10} = \frac{1 \cdot 10}{3 \cdot 10} - \frac{3 \cdot 3}{10 \cdot 3} = \frac{10}{30} - \frac{9}{30} = \frac{10 - 9}{30} = \frac{1}{30} \)
4. \( \frac{5}{12} : \frac{9}{20} = \frac{5}{12} \cdot \frac{20}{9} = \frac{5 \cdot 20}{12 \cdot 9} = \frac{5 \cdot 4 \cdot 5}{3 \cdot 4 \cdot 9} = \frac{25}{27} \)
5. \( (\frac{5}{7} + \frac{3}{18}) + \frac{2}{7} = (\frac{5}{7} + \frac{2}{7}) + \frac{3}{18} = \frac{7}{7} + \frac{3}{18} = 1 + \frac{1}{6} = 1\frac{1}{6} \)
6. \( 16\frac{19}{40} - (13 + 1\frac{19}{40}) = 16\frac{19}{40} - 13 - 1\frac{19}{40} = (16\frac{19}{40} - 1\frac{19}{40}) - 13 = 15 - 13 = 2 \)

Ответ: а) \( \frac{23}{30} \); б) \( \frac{21}{80} \); в) \( \frac{1}{30} \); г) \( \frac{25}{27} \); д) \( 1\frac{1}{6} \); е) 2.