Ответ:

  1. \(\dfrac12-\dfrac14=\dfrac24-\dfrac14=\dfrac14\).
  2. \(\dfrac59-\dfrac13=\dfrac59-\dfrac39=\dfrac29\).
  3. \(\dfrac7{10}-\dfrac35=\dfrac7{10}-\dfrac6{10}=\dfrac1{10}\).
  4. \(\dfrac{16}{27}-\dfrac19=\dfrac{16}{27}-\dfrac3{27}=\dfrac{13}{27}\).
  5. \(\dfrac35-\dfrac{13}{45}=\dfrac{27}{45}-\dfrac{13}{45}=\dfrac{14}{45}\).
  6. \(\dfrac13-\dfrac8{27}=\dfrac9{27}-\dfrac8{27}=\dfrac1{27}\).
  7. \(\dfrac12-\dfrac13=\dfrac36-\dfrac26=\dfrac16\).
  8. \(\dfrac35-\dfrac13=\dfrac9{15}-\dfrac5{15}=\dfrac4{15}\).
  9. \(\dfrac78-\dfrac23=\dfrac{21}{24}-\dfrac{16}{24}=\dfrac5{24}\).
  10. \(\dfrac34-\dfrac47=\dfrac{21}{28}-\dfrac{16}{28}=\dfrac5{28}\).
  11. \(\dfrac9{16}-\dfrac{11}{24}=\dfrac{27}{48}-\dfrac{22}{48}=\dfrac5{48}\).
  12. \(\dfrac{11}{12}-\dfrac{11}{18}=\dfrac{33}{36}-\dfrac{22}{36}=\dfrac{11}{36}\).

Ответ: а) \(\dfrac14\); б) \(\dfrac29\); в) \(\dfrac1{10}\); г) \(\dfrac{13}{27}\); д) \(\dfrac{14}{45}\); е) \(\dfrac1{27}\); ж) \(\dfrac16\); з) \(\dfrac4{15}\); и) \(\dfrac5{24}\); к) \(\dfrac5{28}\); л) \(\dfrac5{48}\); м) \(\dfrac{11}{36}\).