Вопрос:

Вычислите значения выражений: 1) \(\frac{7}{8}\cdot1\frac{5}{7}+\frac{2}{9}\cdot2{,}7\); 2) \(4{,}6+\left(5{,}4+3\frac{2}{3}\right)\cdot\frac{3}{8}\); 3) \(-9+\frac{1}{3}+\frac{2}{5}\); 4) \(-2\frac{1}{7}:4\frac{1}{6}:\left(-\frac{3}{7}\right)\); 5) \(-42+14+25-65+1\).

Ответ:

  1. \(\frac{7}{8}\cdot\frac{12}{7}+\frac{2}{9}\cdot2{,}7=\frac32+0{,}6=2{,}1\).
  2. \(4{,}6+\left(5{,}4+3\frac23\right)\cdot\frac38=4{,}6+\frac{272}{15}\cdot\frac38=4{,}6+\frac{34}{5}=11{,}4\).
  3. \(-9+\frac13+\frac25=-9+\frac{11}{15}=-8\frac4{15}\).
  4. \(-2\frac17:4\frac16:\left(-\frac37\right)=-\frac{15}{7}:\frac{25}{6}\cdot\left(-\frac73\right)=\frac{18}{35}\).
  5. \(-42+14+25-65+1=-67\).

Ответ: 1) 2,1; 2) 11,4; 3) \(-8\frac4{15}\); 4) \(\frac{18}{35}\); 5) −67.