递等式计算,能简便就简便.①、1又1/8+(5又1/2-0.35)×0.4 ②、1.5+(7又3/5-2.6)×1又1/

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  • ①、1又1/8+(5又1/2-0.35)×0.4

    解,得:

    ==(9/8)+(5.5-0.35)*0.4

    ==1.125+5.5*0.4-0.35*0.4

    ==1.125+2.2-0.14

    ==3.45-0.14

    ==3.31

    ②、1.5+(7又3/5-2.6)×1又1/2+(3-1又1/2)×94

    解,得:

    ==1.5+(7.6-2.6)*1.5+(3-1.5)*94

    ==1.5*(1+5+1)*94

    ==1.5*7*94

    ==10.5*(100-6)

    ==1050-63

    ==987

    ③、7.8÷【1.6×(1-3/8)+6.8】

    解,得:

    ==7.8÷【1.6×0.625+6.8】

    ==7.8÷【1+6.8】

    ==7.8÷7.8

    ==1

    ④、1.4+(3/8-0.25)÷1又1/4

    解,得:

    ==1.4+(3/8-0.25)÷1.25

    ==1.4+0.125÷1.25

    ==1.4+0.1

    ==1.5

    ⑤、1.4×3又2/9-1又2/5×2又2/9

    解,得:

    ==(7/5)*(29/9)-(7/5)*(20/9)

    ==(7/5)*[(29/9)-(20/9)]

    ==(7/5)*1

    ==7/5

    ⑥、(8/15+0.45×2/3)÷2又1/12

    解,得:

    ==[(8/15)+(9/20)×(2/3)]÷(25/2)

    ==[(8/15)+(3/10)]*(2/25)

    ==(5/6)*(2/25)

    ==1/15

    ⑦、53.2÷【(6.5-2又1/4)÷8又1/2】

    解,得:

    ==53.2÷【(6.5-2.25)÷8.5】

    ==53.2÷【4.25÷8.5】

    ==53.2÷0.5

    ==106.4