(3 2/3-1,8):2 4/5; х:3,5=0,8:20
(3 2/3-1,8):2 4/5=(11/3-9/5)*5/14= (55/15-27/15)*5/14= 28/15*5/14=2/3;//// х:3,5=0,8:20; х=3,5*0,8:20; Х=0,14