用你自己喜欢的方法计算．（要求写出计算过程）．①〔449-（49+134×2）〕÷215②0.68×724-572×1725+79×68%③〔1113+249×（238-2.375）〕×1314÷717④10.45÷〔（7512-149）×1.8-0.65÷216〕

Question

用你自己喜欢的方法计算．（要求写出计算过程）．
①〔4(4)/(9)-（(4)/(9)+1(3)/(4)×2）〕÷2(1)/(5)
②0.68×(7)/(24)-(5)/(72)×(17)/(25)+(7)/(9)×68%
③〔1(1)/(13)+2(4)/(9)×（2(3)/(8)-2.375）〕×(13)/(14)÷7(1)/(7)
④10.45÷〔（7(5)/(12)-1(4)/(9)）×1.8-0.65÷2(1)/(6)〕

Answer 1

①[4(4)/(9)-（(4)/(9)+1(3)/(4)×2）]÷2(1)/(5)
=[4(4)/(9)-(4)/(9)-3(1)/(2)]÷2(1)/(5)，
=(1)/(2)×(5)/(11)，
=(5)/(22)；

②0.68×(7)/(24)-(5)/(72)×(17)/(25)+(7)/(9)×68%
=0.68×(7)/(24)-(5)/(72)×0.68+(7)/(9)×0.68，
=（(7)/(24)-(5)/(72)+(7)/(9)）×0.68，
=1×0.68，
=0.68；

③[1(1)/(13)+2(4)/(9)×（2(3)/(8)-2.375）]×(13)/(14)÷7(1)/(7)，
=[(14)/(13)+2(4)/(9)×（2.375-2.375）]×(13)/(14)×(7)/(50)，
=[