Ответ:

  1. \(\frac8{26}\cdot\frac5{60}=\frac4{13}\cdot\frac1{12}=\frac1{39}\).
  2. \(\frac56\cdot\frac79=\frac{35}{54}\).
  3. \(\frac{37}{88}\cdot\frac{24}{37}=\frac{24}{88}=\frac3{11}\).
  4. \(\frac{27}{50}\cdot\frac{35}{81}=\frac13\cdot\frac{7}{10}=\frac7{30}\).

Ответ: 1) \(\frac1{39}\); 2) \(\frac{35}{54}\); 3) \(\frac3{11}\); 4) \(\frac7{30}\).