小数乘法简便运算
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简介
乘法交换律：a×b=b×a 乘法结合律：(a×b)×c=a×(b×c) 乘法分配律：(a+b)×c=a×c+b×c 1、拆加型 2.5×10.4 =2.5×(10+0.4) =2.5×10+2.5×0.4 =25+1 =26 2、拆减型 3.5×9.8 =3.5×(10-0.2) =3.5×10-3.5×0.2 =35-0.7 =34.3 3、顺展型 12.5×(8+0.4) =12.5×8+12.5×0.4 =100+5 =105
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