2又5分之4×(-7分之4)+8.75×(-7分之4)+1.2×(-7分之4)-2又4分之3×(-7分之4)

问题描述:

2又5分之4×(-7分之4)+8.75×(-7分之4)+1.2×(-7分之4)-2又4分之3×(-7分之4)

2又(4/5)×(-4/7)+8.75×(-4/7)+1.2×(-4/7)-2又(3/4)×(-4/7)=(2又(4/5)+8.75+1.2-2又(3/4))×(-4/7)=((14/5)+8.75+1.2-(11/4))×(-4/7)=(2.8+8.75+1.2-2.75)×(-4/7)=10×(-4/7)=-40/7=-5又(5/7)