star1224521
春芽
共回答了19个问题采纳率:100% 举报
12/13×2/5-1/3÷5
=24/65-1/3×1/5
=24/65-1/15
=72/195-13/195
=59/195
21又89/90-1又13/20+2又14/15-6又11/15
=21又178/180-1又117/180+2又168/180-6又132/180
=(21-1+2-6)+(178/180-117/180+168/180-132/180)
=16+97/180
=16又97/180
1年前
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