15÷4分之9×5分之3
=15x4/9×3/5
=12/3x5/3x3/5
=4
（6分之5-5分之4+15分之1）×30
=30x5/6-30x4/5+30/15
=25-24+2
=-1
9分之5÷12分之7×10分之7
=5/9x12/7x7/10
=5/9x6/5
=2/3
7分之6×9分之8÷7分之6×9分之8
=6/7x8/9x7/6x8/9
=6/7x7/6x8/9x8/9
=64/81
2-9分之2-15分之7÷5分之3
=2-2/9-7/15x5/3
=2-2/9-7/9
=2-1
=1