66×65分之9 =(65+1)×9/65=65×9/65+1×9/65=9+9/65=9又9/6525×22分之7 =（22+3）*7/22=22*7/22+21/22=7+21/22=7又21/22127×126分之5=(126+1)*5/126=126*5/126+5/126=5+5/126=5又5/1265分之4÷4-4÷5分之4=1/5-5=...