0.84×1.2=4.48÷3.2=536÷0.4=0.58×3.2=7÷0.35=8×0.25×1250.68+1.8÷5+7.612.43×99+2.4338.5×7.2+38.5×2.8.
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解:(1)0.84×1.2=1.008;
?? 0.8 4
?
;
(2)4.48÷3.2=1.4;
(3)536÷0.4=1340;
(4)0.58×3.2=1.856;
?? 0.5 8
??
? ;
(5)7÷0.35=20;
(6)8×0.25×125,
=8×125×0.25,
=1000×0.25,
=250;
(7)0.68+1.8÷5+7.61,
=0.68+0.36+7.61,
=1.04+7.61,
=8.65;
(8)2.43×99+2.43,
=2.43×(99+1),
=2.43×100,
=243;
(9)38.5×7.2+38.5×2.8,
=38.5×(7.2+2.8),
=38.5×10,
=385.
解析分析:(1)(4)根据小数乘法竖式计算的方法求解;
(2)(3)(5)根据小数除法竖式计算的方法求解;
(6)运用乘法交换律简算;
(7)先算除法,再从左到右计算加法;
(8)(9)运用乘法分配律简算.
点评:竖式计算注意把数位对齐,混合运算注意选择合适的方法进行简算.