4 1/3:(5/6+0,25/(7/12-2/15)/3,6*(7/12+1/9)/(5/8-1/3)*1 5/7

1. 4 1/3:(5/6+0,25)= 45/6+0,25=5/6+25/100=5*100+25*6/600=500+150/600=650/600=13/124 1/3:13/12=13/3:13/12=13*12/3*13=156/39=42. 3,6*(7/12+1/9)=2,57/12+1/9=7*9+1*12/108=63+12/108=75/1083,6*75/108=36/10*75/108=36*75/10*108=2700/1080=2,5.(7/12-2/15):0,9=0,57/12-2/15=7*15-2*12/180=105-24/180=81/180=0,450,45:0,9=0,54. (5/8-1/3)*1 5/7=0,55/8-1/3=5*3-1*8/24=15-8/24=7/247/24*1 5/7=7/24*12/7=7*12/24*7=84/168=0,5