3/5×99+3/5
＝3/5x(99+1)
=3/5x100
=60
(7/8+5/6-3/4)×24
=7/8x24+5/6x24-3/4x24
=21+20-18
=23
27×25%+73×1/4
=1/4x(27+73)
=1/4x100
=25采纳即可，不用客气