Выполни сложение и вычитание обыкновенных дробей: a) + = 11 7 8 3 д) + = 15 5 4 2 б) - = 9 11 e) - = 25 4 11 5 B) + = 18 9 *+= 15 7 4 r) - = 9 27

Пошаговое решение:

a) \[ \frac{5}{11} + \frac{4}{7} = \frac{5 \times 7}{11 \times 7} + \frac{4 \times 11}{7 \times 11} = \frac{35}{77} + \frac{44}{77} = \frac{79}{77} \]

д) \[ \frac{8}{15} + \frac{3}{5} = \frac{8}{15} + \frac{3 \times 3}{5 \times 3} = \frac{8}{15} + \frac{9}{15} = \frac{17}{15} \]

б) \[ \frac{4}{9} - \frac{2}{11} = \frac{4 \times 11}{9 \times 11} - \frac{2 \times 9}{11 \times 9} = \frac{44}{99} - \frac{18}{99} = \frac{26}{99} \]

e) \[ \frac{9}{25} - \frac{1}{4} = \frac{9 \times 4}{25 \times 4} - \frac{1 \times 25}{4 \times 25} = \frac{36}{100} - \frac{25}{100} = \frac{11}{100} \]

в) \[ \frac{11}{18} + \frac{5}{9} = \frac{11}{18} + \frac{5 \times 2}{9 \times 2} = \frac{11}{18} + \frac{10}{18} = \frac{21}{18} \]

ж) \[ \frac{2}{15} + \frac{2}{9} = \frac{2 \times 3}{15 \times 3} + \frac{2 \times 5}{9 \times 5} = \frac{6}{45} + \frac{10}{45} = \frac{16}{45} \]

г) \[ \frac{7}{9} - \frac{4}{27} = \frac{7 \times 3}{9 \times 3} - \frac{4}{27} = \frac{21}{27} - \frac{4}{27} = \frac{17}{27} \]

Ответ: a) \(\frac{79}{77}\); д) \(\frac{17}{15}\); б) \(\frac{26}{99}\); e) \(\frac{11}{100}\); в) \(\frac{21}{18}\); ж) \(\frac{16}{45}\); г) \(\frac{17}{27}\)