Ответ:
Пошаговое объяснение:
1) (1/12+1/6):(3/8-1/4)=(1/12+2/12):(3/8-2/8)=3/12:1/8=1/4*8/1=2/1=2
2) (1-4/9):(1/3-1/4)=(9/9-4/9):(4/12-3/12)=5/9:1/12=5/9*12/1=5*4/3=20/3=6 2/3
3) (1/3-5/16):(1/6-1/8)=(16/48-15/48):(4/24-3/24)=1/48:1/24=1/48*24/1=1/2
4) (5/7-2/3):(4/9-5/12)=(15/21-14/21):(16/36-15/36)=1/21:1/36=1/21*36/1=1/3*7 *3*12/1=12/7=1 5/7