第1题:4又3/5÷5又2/5×1/4+0.25
=23/5÷27/5×1/4+1/4
=23/5×5/27×1/4+1/4
=23/27×1/4+1/4
=(23/27+1)×1/4
=50/27×1/4
=25/54
第2题:2/5×60%+19/20×2/5+19/20×60%
=(60%+19/20)×2/5+19/20×60%
=31/20×2/5+57/100
=62/100+57/100
=119/100
第3题:(9/5+8/3)÷[(4-11/6)÷13/4]
=67/15÷[13/6×4/13]
=67/15÷2/3
=67/15×3/2
=67/10
供你参考.