1)(3/4-1/6)*3/7=1/4
1.3/4-1/6=18/24-4/24=14/24
2.14/24*3/7=2/8=1/4
2)(4/15+2/3):2/5=2 1/3
1.4/15+2/3=8/30+20/30=28/30=14/15
2.14/15:2/5=14/15*2/5=7/3=2 1/3
3)(4/9+1/6)*9/11=1/2
1.4/9+1/6=8/18+3/18=11/18
2.11/18*9/11=1/2
4)8/11*(5/6-3/8)=1/3
1.5/6-3/8=20/24-9/24=11/24
2.8/11*11/24=1/3