Выполните сложение: a) 4/7 + 5/6, г) 5/18 + 7/30, ж) 15/19 + 27/37...

Для сложения дробей нужно привести их к общему знаменателю. a) $\frac{4}{7} + \frac{5}{6} = \frac{4 \cdot 6}{42} + \frac{5 \cdot 7}{42} = \frac{24+35}{42} = \frac{59}{42} = 1\frac{17}{42}$ б) $\frac{5}{12} + \frac{2}{15} = \frac{5 \cdot 5}{60} + \frac{2 \cdot 4}{60} = \frac{25+8}{60} = \frac{33}{60} = \frac{11}{20}$ в) $\frac{3}{7} + \frac{5}{14} = \frac{3 \cdot 2}{14} + \frac{5}{14} = \frac{6+5}{14} = \frac{11}{14}$ г) $\frac{5}{18} + \frac{7}{30}$. НОК(18, 30) = 90. $\frac{5 \cdot 5}{90} + \frac{7 \cdot 3}{90} = \frac{25+21}{90} = \frac{46}{90} = \frac{23}{45}$ д) $\frac{13}{25} + \frac{7}{10}$. НОК(25, 10) = 50. $\frac{13 \cdot 2}{50} + \frac{7 \cdot 5}{50} = \frac{26+35}{50} = \frac{61}{50} = 1\frac{11}{50}$ е) $\frac{8}{9} + \frac{7}{12}$. НОК(9, 12) = 36. $\frac{8 \cdot 4}{36} + \frac{7 \cdot 3}{36} = \frac{32+21}{36} = \frac{53}{36} = 1\frac{17}{36}$ ж) $\frac{15}{19} + \frac{27}{37}$. НОК(19, 37) = 703. $\frac{15 \cdot 37}{703} + \frac{27 \cdot 19}{703} = \frac{555 + 513}{703} = \frac{1068}{703} = 1\frac{365}{703}$ з) $\frac{4}{21} + \frac{5}{7} = \frac{4}{21} + \frac{5 \cdot 3}{21} = \frac{4+15}{21} = \frac{19}{21}$ и) $0,22 + \frac{3}{25} + \frac{1}{20} = \frac{22}{100} + \frac{12}{100} + \frac{5}{100} = \frac{22+12+5}{100} = \frac{39}{100} = 0,39$