考点:小数四则混合运算
专题:运算顺序及法则
分析:①4.72×2.5×0.4,运用乘法结合律简算;
②1.5×105,转化为:1.5×(100+5),运用乘法分配律简算;
③1.5×4.8-4.8÷1.6,先算乘法、除法,再算减法;
④35×4.2×7.4,按照从左到右的顺序计算;
⑤1.2×2.5+1.2×5.5,运用乘法分配律简算;
⑥32.5÷0.64×5,先算除法、再算乘法;
⑦2.3÷0.46×2.3,先算除法,再算乘法;
⑧8.3×1.7+8.3×8.3,运用乘法分配律简算.
解答:
解:①4.72×2.5×0.4
=4.72×(2.5×4)
=4.72×10
=47.2;
②1.5×105
=1.5×(100+5)
=1.5×100+1.5×5
=150+7.5
=157.5;
③1.5×4.8-4.8÷1.6
=7.2-3
=4.2;
④35×4.2×7.4
=147×7.4
=1087.8;
⑤1.2×2.5+1.2×5.5
=1.2×(2.5+5.5)
=1.2×8
=9.6;
⑥32.5÷0.64×5
=50.78125×5
=253.90625;
⑦2.3÷0.46×2.3
=5×2.3
=11.5;
⑧8.3×1.7+8.3×8.3
=8.3×(1.7+8.3)
=8.3×10
=83.
点评:此题考查的目的是理解掌握小数四则混合运算的顺序以及它们的计算法则,并且能够灵活选择简便方法进行计算.