(1.25+2.5)*3.2如何巧算?

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(1.25+2.5)*3.2如何巧算?

(1.25+2.5)*3.2如何巧算?
(1.25+2.5)*3.2如何巧算?

(1.25+2.5)*3.2如何巧算?
(1.25+2.5)*3.2
=(1.25+2.5)*0.8*4
=1.25*0.8*4+2.5*4*0.8
=4+8
=12

原式=3×1.25×0.8×4=3×1×4=12

1.25*3.2加1.25*3.2

(1.25*8)+(2.5*0.4)

问题补充: (要有过程) =(1.25X8)X(2.5X0.4)X0.45 =10X1X0.45 =4.5