5/9×0.75×8/15
=5/9*3/4*8/15
=5*3*8/(9*4*15)
=2/9
3/5×3/7+3/5×4/7
=3/5*((3/7+4/7)
=3/5
（1-4/5×1/12）÷1/3
=(1-1/15)*3
=14/5
3/25×124
=3/25*(125-1)
=15-3/25
=14又22/25