4 целых 1\6-1 целая 1\5= 12*5\18= 6:1 целая 1\5=
12*5/18=(12*5)/18=60/18=3 6/18=3 1/3 ------------------- 6:1 1/5=6/1:6/5=6/1*5/6=5/1=5