31/60+(21/60+11/60)=31/60+32/60=63/69
13/35+(23/35-10/35)=13/35+13/35=26/35
53/54-(3/18+14/18)=53/54-17/18=53/54-51/54=2/54
7/16-(12/16-5/16)=7/16-7/16=0
1) 31/60+(7/20+11/60)=31/60+32/60=63/60=21/20
2) 13/35+(23/35-2/7)=13/35+13/35=26/35
3)53/54-(1/6+7/9)=53/54-17/18=53/54-51/54=2/54=1/27
4)7/16-(3/4-5/16)=7/16-7/16=0
Вроде так)
31/60+(21/60+11/60)=31/60+32/60=63/69
13/35+(23/35-10/35)=13/35+13/35=26/35
53/54-(3/18+14/18)=53/54-17/18=53/54-51/54=2/54
7/16-(12/16-5/16)=7/16-7/16=0
1) 31/60+(7/20+11/60)=31/60+32/60=63/60=21/20
2) 13/35+(23/35-2/7)=13/35+13/35=26/35
3)53/54-(1/6+7/9)=53/54-17/18=53/54-51/54=2/54=1/27
4)7/16-(3/4-5/16)=7/16-7/16=0
Вроде так)