а) 25/80+45/60=5/16+3/4=5/16+12/16=17/16=1 1/16
г) 20/45+26/54=4/9+13/27=12/27+13/27=25/27
б) 36/300+12/40-350/1000=12/100+3/10-35/100=12/100+30/100-35/100=7/100
в) 42/120+20/32-28/160=14/40+5/8-7/40=14/40+25/40-7/40=32/40=4/5
д) 14/24-39/90+15/100=7/12-13/30+3/20=35/60-26/60+9/60=18/60=3/10
е) 45/72-33/144-20/64=5/8-11/48-5/16=30/48-11/48-15/48=4/48=1/12