Ответ:
а) Знаменатели одинаковые:
\(\frac49+\frac79-\frac19=\frac{4+7-1}{9}=\frac{10}{9}=1\frac19\).
б)
\(5\frac6{39}+4\frac7{78}=9+\frac2{13}+\frac7{78}=9+\frac{12}{78}+\frac7{78}=9\frac{19}{78}\).
в)
\(\frac67-\left(\frac57-\frac17\right)=\frac67-\frac47=\frac27\).
г)
\(7\frac{13}{15}-3\frac{11}{30}=4+\frac{26}{30}-\frac{11}{30}=4\frac{15}{30}=4\frac12\).
д)
\(\frac78\cdot\frac4{35}\cdot\frac{10}{9}=\frac{7\cdot4\cdot10}{8\cdot35\cdot9}=\frac19\).
е)
\(\left(\frac12:\frac34-\frac49\right)\cdot\frac53=\left(\frac12\cdot\frac43-\frac49\right)\cdot\frac53=\left(\frac23-\frac49\right)\cdot\frac53=\frac29\cdot\frac53=\frac{10}{27}\).
Ответ: а) \(1\frac19\); б) \(9\frac{19}{78}\); в) \(\frac27\); г) \(4\frac12\); д) \(\frac19\); е) \(\frac{10}{27}\).
