3.25×0.8—0.8
=（3.25-1）×0.8
=2.25×0.8
=18
7分之4÷5分之2÷7×2
=4/7*5/2*7/2
=5
9分之7+3分之2÷26
=9分之7+39分之1
=94/117
25000×4.14%×5
=5175