5.168 Выполните сложение и вычитание: a) \(\frac{4}{9} + \frac{2}{9}\) б) \(\frac{1}{11} + \frac{5}{11}\) в) \(\frac{12}{19} + \frac{7}{19}\) г) \(\frac{13}{1000} + \frac{2}{10}\)

Решение:

а) \( \frac{4}{9} + \frac{2}{9} = \frac{4+2}{9} = \frac{6}{9} = \frac{2}{3} \)

б) \( \frac{1}{11} + \frac{5}{11} = \frac{1+5}{11} = \frac{6}{11} \)

в) \( \frac{12}{19} + \frac{7}{19} = \frac{12+7}{19} = \frac{19}{19} = 1 \)

г) \( \frac{13}{1000} + \frac{2}{10} = \frac{13}{1000} + \frac{2 \cdot 100}{10 \cdot 100} = \frac{13}{1000} + \frac{200}{1000} = \frac{13+200}{1000} = \frac{213}{1000} \)

Ответ: а) \(\frac{2}{3}\), б) \(\frac{6}{11}\), в) 1, г) \(\frac{213}{1000}\).