5分之3*6分之1*7分之5
=3/5*5/7*1/6
=3/7*1/6
=1/14
9分之8/7分之4/3分之1
=8/9*7/4*3
=14/9*3
=14/3
14分之5/21分之4*0.64
=5/14*21/4*0.64
=5/8*0.64
=0.4
2-13分之6/26分之9-3分之2
=2-6/13*26/9-2/3
=2-4/3-2/3
=2-（4/3+2/3）
=2-2
=0
(0.75-16分之3)*(9分之2+3分之1)
=（3/4-3/16）*5/9
=9/16*5/9
=5/16