1/3 : (5/6+0,25)=1/3 : (5/6+1/4)=1/3 : (10/12+3/12)=1/3 : 13/12=1/3 * 12/13=4/13
3,6*(7/12+1/9)=3,6*(21/36+4/36)=(36/10) * (25/36)= 25/10=2,5
(7/12-2/15):0,9 = (35/60-8/60): (9/10)= 27/60* 10/9=9/20* 10/9=1/2
(5/8-1/3)*1 5/7=(15/24-8/24)*12/7=7/24*12/7=1/2