Ответ:

  1. \(\frac{28}{36}=\frac{28:4}{36:4}=\frac79\).
  2. \(\frac{56}{28}=2\).
  3. \(\frac{114}{171}=\frac{114:57}{171:57}=\frac23\).
  4. \(\frac{102}{153}=\frac{102:51}{153:51}=\frac23\).
  5. \(\frac{6\cdot15}{5\cdot12}=\frac{90}{60}=\frac32\).
  6. \(\frac{6\cdot8\cdot18}{4\cdot12\cdot27}=\frac{864}{1296}=\frac23\).