3/4-(5/7-2/5)=3/4-(25/35-14/35)=3/4-11/35=105/140-44/140=61/140希望采纳,谢谢
分数计算3/4-(5/7-2/5)=3/4-(25/35-14/35)=3/4-11/35=105/140-44/140=61/140