7.5乘99.9怎么简便运算?

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7.5乘99.9怎么简便运算?

7.5乘99.9怎么简便运算?
7.5乘99.9怎么简便运算?

7.5乘99.9怎么简便运算?
7.5x99.9
=7.5x(100-0.1)
=7.5x100-7.5x0.1
=750-0.75
=749.25

=7.5×(100-0.1)
=7.5×100-7.5×0.1
=750-0.75
=749.25

7.5乘99.9
=7.5×100-7.5×0.1
=750-0.75
=749.15

=7.5*(100-0.1)=750-0.75=749.25

额。。这个是 7.5*100 - 7.5*0.01 = 750 - 0.075 =749.925

7.5x99.9=7.5x(100-0.1)=7.5x100-7.5x0.1=750-0.75=749.25

100乘以7.5再减去0.75就行了!100是99.9+0.1得来的,0.75是加的那0.1乘以7.5得来的!