Ответ:

  1. \(5/8+5/6=15/24+20/24=35/24=1\ 11/24\).
  2. \(3/20-1/50=15/100-2/100=13/100\).
  3. \(8/51+3/17=8/51+9/51=17/51=1/3\).
  4. \(1/3-1/6=2/6-1/6=1/6\).
  5. Преобразуем десятичную дробь: \(0.35-1/20=0.35-0.05=0.3\).
  6. \(1/15-1/30=2/30-1/30=1/30\).
  7. \(3/10-2/15=9/30-4/30=5/30=1/6\).
  8. \(1/6+8/9=3/18+16/18=19/18=1\ 1/18\).
  9. \(3/5+0.4=0.6+0.4=1\).
  10. \(23/45+13/30=46/90+39/90=85/90=17/18\).
  11. \(1/4+0.5=1/4+1/2=3/4\).
  12. \(3/4+1/6=9/12+2/12=11/12\).
  13. \(13/14-5/42=39/42-5/42=34/42=17/21\).
  14. \(1/8-1/16=2/16-1/16=1/16\).
  15. \(7/12+11/18=21/36+22/36=43/36=1\ 7/36\).