脱式计算(能简算的药简算) 12.5×0.4×2.5×80.87×6.6+8.7×0.349.07-22.78÷3.4.
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解:(1)12.5×0.4×2.5×8,
=(12.5×8)×(0.4×2.5),
=100×1,
=100;
(2)0.87×6.6+8.7×0.34,
=0.87×6.6+0.87×10×0.34,
=0.87×6.6+0.87×3.4,
=0.87×(6.6+3.4),
=0.87×10,
=8.7;
(3)9.07-22.78÷3.4,
=9.07-6.7,
=2.37.
解析分析:(1)根据乘法交换律和结合律计算,
(2)根据乘法分配律进行计算,
(3)先算除法,再算减法.
点评:本题综合考查了学生小数四则运算的计算能力,以及在计算中灵活运用简便算法的能力.